Fix the MIPS coherency configuration such that we always keep the mapping
state in <asm/pci.h> when we need to on non-coherent platforms.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>