MIPS: Probe cache line sizes once during boot

Rather than probing the cache line sizes on every call of any cache
maintenance function, probe them once during boot & store the values in
the global data structure for later use. This will reduce the overhead
of the cache maintenance functions, which isn't a big deal yet but
becomes more important once L2 caches which may expose their properties
via coprocessor 2 or the CM are supported.

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

arch/mips/include/asm/global_data.h

@@ -21,6 +21,10 @@ struct arch_global_data {
 	unsigned long rev;
 	unsigned long ver;
 #endif
+#ifdef CONFIG_SYS_CACHE_SIZE_AUTO
+	unsigned short l1i_line_size;
+	unsigned short l1d_line_size;
+#endif
 };
 
 #include <asm-generic/global_data.h>