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/dbau1x00/Kconfig b/board/dbau1x00/Kconfig
index 342ec59..1715a28 100644
--- a/board/dbau1x00/Kconfig
+++ b/board/dbau1x00/Kconfig
@@ -12,6 +12,15 @@
 config SYS_TEXT_BASE
 	default 0xbfc00000
 
+config SYS_DCACHE_SIZE
+	default 16384
+
+config SYS_ICACHE_SIZE
+	default 16384
+
+config SYS_CACHELINE_SIZE
+	default 32
+
 menu "dbau1x00 board options"
 
 choice