imx: imx6_spl add mx6ul support

i.MX6UL's DRAM space starts from 0x80000000, same to i.MX6SX, so use
same address with i.MX6SX.

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>

include/configs/imx6_spl.h

@@ -61,7 +61,7 @@
 #define CONFIG_SPL_LIBDISK_SUPPORT
 #endif
 
-#if defined(CONFIG_MX6SX)
+#if defined(CONFIG_MX6SX) || defined(CONFIG_MX6UL)
 #define CONFIG_SPL_BSS_START_ADDR      0x88200000
 #define CONFIG_SPL_BSS_MAX_SIZE        0x100000        /* 1 MB */
 #define CONFIG_SYS_SPL_MALLOC_START    0x88300000