microblaze: Do not use CONFIG_SYS_GENERIC_GLOBAL_DATA

Because it is not compatible with DM where
malloc_base has to be available early and init
has to be done in ASM.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/microblaze/cpu/start.S

@@ -151,6 +151,7 @@ clear_bss:
 3:	/* jumping to board_init */
 #ifndef CONFIG_SPL_BUILD
 	or	r5, r0, r0	/* flags - empty */
+	addi    r31, r0, _gd
 	brai	board_init_f
 #else
 	addi	r31, r0, CONFIG_SYS_SPL_MALLOC_END
@@ -158,6 +159,11 @@ clear_bss:
 #endif
 1:	bri	1b
 
+ .section .bss
+.align 4
+_gd:
+         .space  GENERATED_GBL_DATA_SIZE
+
 #ifndef CONFIG_SPL_BUILD
 /*
  * Read 16bit little endian

arch/microblaze/include/asm/config.h

@@ -13,6 +13,5 @@
 
 #define CONFIG_NR_DRAM_BANKS	1
 #define CONFIG_SYS_GENERIC_BOARD
-#define CONFIG_SYS_GENERIC_GLOBAL_DATA
 
 #endif