MIPS: Delete redundant definition of SMP_CACHE_BYTES.

<linux/cache.h> already defines SMP_CACHE_BYTES as L1_CACHE_BYTES.

This change results in a build error in <asm/cpu-info.h> which directly
includes <asm/cache.h>.  Fix this by including <linux/cache.h> instead.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>