MIPS: Add fast get_user_pages

Gup is used in a few cases, say futex.

This work is derived from the x86 version, and operations of pte and pmd are
adapted to the defines of MIPS in straight forward manner.

[ralf@linux-mips.org: Fixed up reject in arch/mips/mm/Makefile due to
whitespace formatting differences.  Fixed build error in gup.c due to
conflicting changes elsewhere in the kernel.]

Signed-off-by: Hillf Danton <dhillf@gmail.com>
Cc: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2859/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/mm/Makefile b/arch/mips/mm/Makefile
index 4d8c162..3ca2a06 100644
--- a/arch/mips/mm/Makefile
+++ b/arch/mips/mm/Makefile
@@ -3,8 +3,8 @@
 #
 
 obj-y				+= cache.o dma-default.o extable.o fault.o \
-				   init.o mmap.o tlbex.o tlbex-fault.o uasm.o \
-				   page.o
+				   gup.o init.o mmap.o page.o tlbex.o \
+				   tlbex-fault.o uasm.o
 
 obj-$(CONFIG_32BIT)		+= ioremap.o pgtable-32.o
 obj-$(CONFIG_64BIT)		+= pgtable-64.o