Revert "MIPS: Fix PAGE_MASK definition"

Revert "MIPS: Fix PAGE_MASK definition"

This reverts commit 86cbc6c14d2a66399e448814ed581c02990dd6b9.

It was originally sent in an earlier revision of the pfn_t patchset.
Besides being broken, the warning is also fixed by PFN_FLAGS_MASK
casting the PAGE_MASK to an unsigned long.

Reported-by: Manuel Lauss <manuel.lauss@gmail.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: linux-kernel@vger.kernel.org
Cc: Linux-MIPS <linux-mips@linux-mips.org>
Cc: stable@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/12182/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>