MIPS: Build fix - include <linux/smp.h> into all smp_processor_id() users.

Some of the were relying into smp.h being dragged in by another header
which of course is fragile.  <asm/cpu-info.h> uses smp_processor_id()
only in macros and including smp.h there leads to an include loop, so
don't change cpu-info.h.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/include/asm/mmu_context.h b/arch/mips/include/asm/mmu_context.h
index d7f3eb0..d3bea88 100644
--- a/arch/mips/include/asm/mmu_context.h
+++ b/arch/mips/include/asm/mmu_context.h
@@ -13,6 +13,7 @@
 
 #include <linux/errno.h>
 #include <linux/sched.h>
+#include <linux/smp.h>
 #include <linux/slab.h>
 #include <asm/cacheflush.h>
 #include <asm/tlbflush.h>