MIPS: Move cache sizes to Kconfig

Move details of the L1 cache line sizes & total sizes into Kconfig,
defaulting to 0. A new CONFIG_SYS_CACHE_SIZE_AUTO Kconfig entry is
introduced to allow platforms to select auto-detection of cache sizes,
and it defaults to being enabled if none of the cache sizes are set by
the configuration (ie. sizes are all the default 0), and code is
adjusted to #ifdef on that rather than on the definition of the sizes
(which will always be defined even if 0).

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
diff --git a/board/qemu-mips/Kconfig b/board/qemu-mips/Kconfig
index 3de1f44..66957e7 100644
--- a/board/qemu-mips/Kconfig
+++ b/board/qemu-mips/Kconfig
@@ -11,4 +11,13 @@
 	default 0xbfc00000 if 32BIT
 	default 0xffffffffbfc00000 if 64BIT
 
+config SYS_DCACHE_SIZE
+	default 16384
+
+config SYS_ICACHE_SIZE
+	default 16384
+
+config SYS_CACHELINE_SIZE
+	default 32
+
 endif