arch: change default endian for microblaze

Fix the default for microblaze. Michal Simek mentioned default for
microblaze should be CPU_LITTLE_ENDIAN.

Fixes : commit 206d3642 ("arch/microblaze: add choice for endianness
	and update Makefile")
Signed-off-by: Babu Moger <babu.moger@oracle.com>
Cc: Michal Simek <monstr@monstr.eu>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/microblaze/Kconfig

@@ -39,7 +39,7 @@ config MICROBLAZE
 # Endianness selection
 choice
 	prompt "Endianness selection"
-	default CPU_BIG_ENDIAN
+	default CPU_LITTLE_ENDIAN
 	help
 	  microblaze architectures can be configured for either little or
 	  big endian formats. Be sure to select the appropriate mode.