mmc: update MMC_ERASE argument to match Linux kernel.

Table 41 of the JEDEC standard for eMMC says that bit 31 of
the command argument is obsolete when issuing the ERASE
command (CMD38) on page 115 of this document:
	http://www.jedec.org/sites/default/files/docs/jesd84-B45.pdf

The SD Card Association Physical Layer Simplified Specification also
makes no mention of the use of bit 31.
	https://www.sdcard.org/downloads/pls/part1_410.pdf

The Linux kernel distinguishes between secure (bit 31 set) and
non-secure erase, and this patch copies the macro names from
include/linux/mmc/core.h.

Tested-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Eric Nelson <eric@nelint.com>
Tested-by: Hector Palacios <hector.palacios@digi.com>

drivers/mmc/mmc_write.c

@@ -51,7 +51,7 @@ static ulong mmc_erase_t(struct mmc *mmc, ulong start, lbaint_t blkcnt)
 		goto err_out;
 
 	cmd.cmdidx = MMC_CMD_ERASE;
-	cmd.cmdarg = SECURE_ERASE;
+	cmd.cmdarg = MMC_ERASE_ARG;
 	cmd.resp_type = MMC_RSP_R1b;
 
 	err = mmc_send_cmd(mmc, &cmd, NULL);

include/mmc.h

@@ -121,7 +121,12 @@
 #define OCR_VOLTAGE_MASK	0x007FFF80
 #define OCR_ACCESS_MODE		0x60000000
 
-#define SECURE_ERASE		0x80000000
+#define MMC_ERASE_ARG		0x00000000
+#define MMC_SECURE_ERASE_ARG	0x80000000
+#define MMC_TRIM_ARG		0x00000001
+#define MMC_DISCARD_ARG		0x00000003
+#define MMC_SECURE_TRIM1_ARG	0x80000001
+#define MMC_SECURE_TRIM2_ARG	0x80008000
 
 #define MMC_STATUS_MASK		(~0x0206BF7F)
 #define MMC_STATUS_SWITCH_ERROR	(1 << 7)