MIPS: kconfig: add options for endianess select

Add new Kconfig option to let the user select the targets
endianess. Each target have to select SUPPORTS_BIG_ENDIAN
and/or SUPPORTS_LITTLE_ENDIAN to indicate which endianess
is supported.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 9b72bab..f2e6a45 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -12,21 +12,31 @@
 
 config TARGET_QEMU_MIPS
 	bool "Support qemu-mips"
+	select SUPPORTS_BIG_ENDIAN
+	select SUPPORTS_LITTLE_ENDIAN
 
 config TARGET_MALTA
 	bool "Support malta"
+	select SUPPORTS_BIG_ENDIAN
+	select SUPPORTS_LITTLE_ENDIAN
 
 config TARGET_VCT
 	bool "Support vct"
+	select SUPPORTS_BIG_ENDIAN
 
 config TARGET_DBAU1X00
 	bool "Support dbau1x00"
+	select SUPPORTS_BIG_ENDIAN
+	select SUPPORTS_LITTLE_ENDIAN
 
 config TARGET_PB1X00
 	bool "Support pb1x00"
+	select SUPPORTS_LITTLE_ENDIAN
 
 config TARGET_QEMU_MIPS64
 	bool "Support qemu-mips64"
+	select SUPPORTS_BIG_ENDIAN
+	select SUPPORTS_LITTLE_ENDIAN
 
 endchoice
 
@@ -36,4 +46,32 @@
 source "board/pb1x00/Kconfig"
 source "board/qemu-mips/Kconfig"
 
+if MIPS
+
+choice
+	prompt "Endianness selection"
+	help
+	  Some MIPS boards can be configured for either little or big endian
+	  byte order. These modes require different U-Boot images. In general there
+	  is one preferred byteorder for a particular system but some systems are
+	  just as commonly used in the one or the other endianness.
+
+config SYS_BIG_ENDIAN
+	bool "Big endian"
+	depends on SUPPORTS_BIG_ENDIAN
+
+config SYS_LITTLE_ENDIAN
+	bool "Little endian"
+	depends on SUPPORTS_LITTLE_ENDIAN
+
+endchoice
+
+config SUPPORTS_BIG_ENDIAN
+	bool
+
+config SUPPORTS_LITTLE_ENDIAN
+	bool
+
+endif
+
 endmenu