[MIPS] local_r4k_flush_cache_page fix

    
If dcache_size != icache_size or dcache_size != scache_size, or
set-associative cache, icache/scache does not flushed properly.  Make
blast_?cache_page_indexed() masks its index value correctly.  Also,
use physical address for physically indexed pcache/scache.
    
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>