vp9_systemdependent: reorder includes avoid proto mismatch

fixes a warning in vs9/x64 related to ceil()

Change-Id: Ic4bde9d0b7e961546dbe304de74aa37fc02fcf94

vp9/common/vp9_systemdependent.h

diff --git a/vp9/common/vp9_systemdependent.h b/vp9/common/vp9_systemdependent.h
index 72edbca..e971158 100644
--- a/vp9/common/vp9_systemdependent.h
+++ b/vp9/common/vp9_systemdependent.h
@@ -12,11 +12,11 @@
 #define VP9_COMMON_VP9_SYSTEMDEPENDENT_H_
 
 #ifdef _MSC_VER
+# include <math.h>  // the ceil() definition must precede intrin.h
 # if _MSC_VER > 1310 && (defined(_M_X64) || defined(_M_IX86))
 #  include <intrin.h>
 #  define USE_MSC_INTRIN
 # endif
-# include <math.h>
 # define snprintf _snprintf
 #endif