[MIPS] Cleanup TO_PHYS_MASK definition

No point in adding yet another #ifdef for Loongson since all this mask is
being used for is converting an XKPHYS address into a physical address
anyway.  So replace all definitions by one with the highest architectural
possible value.

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