MIPS: kconfig: add option for MIPS_L1_CACHE_SHIFT

Add Kconfig symbol for L1 cache shift like the kernel does.
The value of CONFIG_SYS_CACHELINE_SIZE is not a reliable source
for ARCH_DMA_MINALIGN anymore, because it is optional on MIPS.
If CONFIG_SYS_CACHELINE_SIZE is not defined by a board, the
cache sizes are automatically detected and ARCH_DMA_MINALIGN
would be set to 128 Bytes.

The default value for CONFIG_MIPS_L1_CACHE_SHIFT is 5 which
corresponds to 32 Bytes. All current MIPS boards already used
that value. While on it, fix the Malta board to use a value of 6
like the kernel port does.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 388e4c0..1b39c4c 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -28,6 +28,7 @@
 	select SUPPORTS_CPU_MIPS32_R1
 	select SUPPORTS_CPU_MIPS32_R2
 	select SWAP_IO_SPACE
+	select MIPS_L1_CACHE_SHIFT_6
 
 config TARGET_VCT
 	bool "Support vct"
@@ -196,6 +197,26 @@
 config SYS_MIPS_CACHE_INIT_RAM_LOAD
 	bool
 
+config MIPS_L1_CACHE_SHIFT_4
+	bool
+
+config MIPS_L1_CACHE_SHIFT_5
+	bool
+
+config MIPS_L1_CACHE_SHIFT_6
+	bool
+
+config MIPS_L1_CACHE_SHIFT_7
+	bool
+
+config MIPS_L1_CACHE_SHIFT
+	int
+	default "7" if MIPS_L1_CACHE_SHIFT_7
+	default "6" if MIPS_L1_CACHE_SHIFT_6
+	default "5" if MIPS_L1_CACHE_SHIFT_5
+	default "4" if MIPS_L1_CACHE_SHIFT_4
+	default "5"
+
 endif
 
 endmenu