vp8cx : bestsad declared and initialized incorrectly.

bestsad needs to be a int and set to INT_MAX because at the end
of the function it is compared to INT_MAX to determine if there
was a match in the function.

Change-Id: Ie80e88e4c4bb4a1ff9446079b794d14d5a219788
diff --git a/vp8/encoder/mcomp.c b/vp8/encoder/mcomp.c
index 6d69a9e..156578b 100644
--- a/vp8/encoder/mcomp.c
+++ b/vp8/encoder/mcomp.c
@@ -1238,7 +1238,7 @@
     unsigned char *bestaddress;
     MV *best_mv = &d->bmi.mv.as_mv;
     MV this_mv;
-    unsigned int bestsad = UINT_MAX;
+    int bestsad = INT_MAX;
     int r, c;
 
     unsigned char *check_here;