sdhc_boot: Introduce CONFIG_FSL_FIXED_MMC_LOCATION option

Since commit 97039ab98 (env_mmc: Allow board code to override the environment address)
mmc_get_env_addr is a weak-aliased function in common/env_mmc.c

The mmc_get_env_addr implementation that exists at
board/freescale/common/sdhc_boot.c is meant to be used only for PowerPC boards,
but currently it is being used for all platforms that have CONFIG_ENV_IS_IN_MMC defined.

Introduce CONFIG_FSL_FIXED_MMC_LOCATION so that the boards that need to use
the mmc_get_env_addr version from board/freescale/common/sdhc_boot.c could activate
this config option on their board file.

This fixes the retrieval of CONFIG_ENV_OFFSET on non-PowerPC boards.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Stefano Babic <sbabic@denx.de>

board/freescale/common/Makefile

@@ -39,7 +39,7 @@ COBJS-$(CONFIG_PQ_MDS_PIB)	+= pq-mds-pib.o
 COBJS-$(CONFIG_ID_EEPROM)	+= sys_eeprom.o
 COBJS-$(CONFIG_FSL_SGMII_RISER)	+= sgmii_riser.o
 ifndef CONFIG_RAMBOOT_PBL
-COBJS-$(CONFIG_ENV_IS_IN_MMC)	+= sdhc_boot.o
+COBJS-$(CONFIG_FSL_FIXED_MMC_LOCATION)	+= sdhc_boot.o
 endif
 
 COBJS-$(CONFIG_MPC8541CDS)	+= cds_pci_ft.o

include/configs/MPC8536DS.h

@@ -659,6 +659,7 @@
 #define CONFIG_ENV_SECT_SIZE	0x10000
 #elif defined(CONFIG_RAMBOOT_SDCARD)
 #define CONFIG_ENV_IS_IN_MMC
+#define CONFIG_FSL_FIXED_MMC_LOCATION
 #define CONFIG_ENV_SIZE		0x2000
 #define CONFIG_SYS_MMC_ENV_DEV  0
 #else

include/configs/P1010RDB.h

@@ -609,6 +609,7 @@ extern unsigned long get_sdram_size(void);
 #if defined(CONFIG_SYS_RAMBOOT)
 #if defined(CONFIG_RAMBOOT_SDCARD)
 #define CONFIG_ENV_IS_IN_MMC
+#define CONFIG_FSL_FIXED_MMC_LOCATION
 #define CONFIG_SYS_MMC_ENV_DEV		0
 #define CONFIG_ENV_SIZE			0x2000
 #elif defined(CONFIG_RAMBOOT_SPIFLASH)

include/configs/P1_P2_RDB.h

@@ -518,6 +518,7 @@ extern unsigned long get_board_sys_clk(unsigned long dummy);
 	#define CONFIG_ENV_OFFSET	((512 * 1024) + CONFIG_SYS_NAND_BLOCK_SIZE)
 #elif defined(CONFIG_RAMBOOT_SDCARD)
 #define CONFIG_ENV_IS_IN_MMC
+#define CONFIG_FSL_FIXED_MMC_LOCATION
 #define CONFIG_ENV_SIZE			0x2000
 #define CONFIG_SYS_MMC_ENV_DEV		0
 #elif defined(CONFIG_RAMBOOT_SPIFLASH)

include/configs/P2020COME.h

@@ -350,6 +350,7 @@ extern unsigned long get_board_sys_clk(unsigned long dummy);
  */
 #if defined(CONFIG_RAMBOOT_SDCARD)
 	#define CONFIG_ENV_IS_IN_MMC	1
+	#define CONFIG_FSL_FIXED_MMC_LOCATION
 	#define CONFIG_ENV_SIZE		0x2000
 	#define CONFIG_SYS_MMC_ENV_DEV	0
 #elif defined(CONFIG_RAMBOOT_SPIFLASH)

include/configs/P2020DS.h

@@ -596,6 +596,7 @@
  */
 #if defined(CONFIG_SDCARD)
 #define CONFIG_ENV_IS_IN_MMC
+#define CONFIG_FSL_FIXED_MMC_LOCATION
 #define CONFIG_ENV_SIZE			0x2000
 #define CONFIG_SYS_MMC_ENV_DEV		0
 #elif defined(CONFIG_SPIFLASH)

include/configs/P2041RDB.h

@@ -92,6 +92,7 @@
 #elif defined(CONFIG_SDCARD)
 	#define CONFIG_SYS_EXTRA_ENV_RELOC
 	#define CONFIG_ENV_IS_IN_MMC
+	#define CONFIG_FSL_FIXED_MMC_LOCATION
 	#define CONFIG_SYS_MMC_ENV_DEV          0
 	#define CONFIG_ENV_SIZE			0x2000
 	#define CONFIG_ENV_OFFSET		(512 * 1097)

include/configs/corenet_ds.h

@@ -88,6 +88,7 @@
 #elif defined(CONFIG_SDCARD)
 #define CONFIG_SYS_EXTRA_ENV_RELOC
 #define CONFIG_ENV_IS_IN_MMC
+#define CONFIG_FSL_FIXED_MMC_LOCATION
 #define CONFIG_SYS_MMC_ENV_DEV          0
 #define CONFIG_ENV_SIZE			0x2000
 #define CONFIG_ENV_OFFSET		(512 * 1097)

include/configs/p1_p2_rdb_pc.h

@@ -733,6 +733,7 @@
 #define CONFIG_ENV_SECT_SIZE	0x10000
 #elif defined(CONFIG_RAMBOOT_SDCARD)
 #define CONFIG_ENV_IS_IN_MMC
+#define CONFIG_FSL_FIXED_MMC_LOCATION
 #define CONFIG_ENV_SIZE		0x2000
 #define CONFIG_SYS_MMC_ENV_DEV	0
 #elif defined(CONFIG_NAND_U_BOOT)