MIPS: c-r4k: Call R4600_HIT_CACHEOP_WAR_IMPL only for 32 byte cache lines.

R4600_HIT_CACHEOP_WAR_IMPL is only needed on R4600 v1.6 and the R4600 has
data cache lines that are always 32 bytes so the call is pointless in
r4k_blast_dcache_page_dc64.

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