malta: Support MIPS32r6 configurations

Both real Malta boards & QEMU's Malta emulation can feature MIPS32r6
CPUs. Allow building U-Boot for such systems by selecting
CONFIG_SUPPORTS_CPU_MIPS32_R6 for Malta.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>

arch/mips/Kconfig

@@ -28,6 +28,7 @@ config TARGET_MALTA
 	select SUPPORTS_LITTLE_ENDIAN
 	select SUPPORTS_CPU_MIPS32_R1
 	select SUPPORTS_CPU_MIPS32_R2
+	select SUPPORTS_CPU_MIPS32_R6
 	select SWAP_IO_SPACE
 	select MIPS_L1_CACHE_SHIFT_6