src/include: Fix unsigned warnings

Fix warning detected by checkpatch.pl:

WARNING: Prefer 'unsigned int' to bare use of 'unsigned'

BRANCH=none
BUG=None
TEST=Build and run on Galileo Gen2

Change-Id: I23d9b4b715aa74acc387db8fb8d3c73bd5cabfaa
Signed-off-by: Lee Leahy <Leroy.P.Leahy@intel.com>
Reviewed-on: https://review.coreboot.org/18607
Reviewed-by: Philippe Mathieu-Daudé <philippe.mathieu.daude@gmail.com>
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>
diff --git a/src/include/cpu/x86/mtrr.h b/src/include/cpu/x86/mtrr.h
index d9f38f5..fb8474a 100644
--- a/src/include/cpu/x86/mtrr.h
+++ b/src/include/cpu/x86/mtrr.h
@@ -87,7 +87,8 @@
 #endif
 
 #if !defined(__ASSEMBLER__) && defined(__PRE_RAM__) && !defined(__ROMCC__)
-void set_var_mtrr(unsigned reg, unsigned base, unsigned size, unsigned type);
+void set_var_mtrr(unsigned int reg, unsigned int base, unsigned int size,
+	unsigned int type);
 int get_free_var_mtrr(void);
 #endif