[MIPS] Fix yosemite build error

<linux/mm.h> didn't pickup the definition of PKMAP_BASE from fixmap.h, ugh.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/include/asm-mips/pgtable-32.h b/include/asm-mips/pgtable-32.h
index a094709..ceefe02 100644
--- a/include/asm-mips/pgtable-32.h
+++ b/include/asm-mips/pgtable-32.h
@@ -65,6 +65,8 @@
 
 #define VMALLOC_START     MAP_BASE
 
+#define PKMAP_BASE		(0xfe000000UL)
+
 #ifdef CONFIG_HIGHMEM
 # define VMALLOC_END	(PKMAP_BASE-2*PAGE_SIZE)
 #else