mx5: Remove unnecessary CONFIG_SYS_BOOTMAPSZ definition

Since the following commit, definition CONFIG_SYS_BOOTMAPSZ is not
needed any more.

  ed59e587
  Remove device tree booting dependency on CONFIG_SYS_BOOTMAPSZ
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>

include/configs/mx51evk.h

@@ -227,6 +227,5 @@
 #define CONFIG_SYS_MMC_ENV_DEV 0
 
 #define CONFIG_OF_LIBFDT
-#define CONFIG_SYS_BOOTMAPSZ   0x800000
 
 #endif

include/configs/mx53evk.h

@@ -193,6 +193,5 @@
 #define CONFIG_SYS_MMC_ENV_DEV 0
 
 #define CONFIG_OF_LIBFDT
-#define CONFIG_SYS_BOOTMAPSZ   0x800000
 
 #endif				/* __CONFIG_H */