Fix a bug in the C selfguided filter

Patch https://aomedia-review.googlesource.com/c/8321/ introduced
a bug in the C version of the self-guided filter in the case where
w = 384 and h > 368 or w > 368 and h = 384. This was due to forgetting
to adjust the offset between A and B in the C code.

This patch sets the offset correctly, resolving this bug.

Change-Id: I6bdf11aa76c37d0ecae02788b262e7a2e0a11a6e

av1/common/restoration.c

diff --git a/av1/common/restoration.c b/av1/common/restoration.c
index 52c7883..5983d54 100644
--- a/av1/common/restoration.c
+++ b/av1/common/restoration.c
@@ -615,7 +615,7 @@
                                 int bit_depth, int r, int eps,
                                 int32_t *tmpbuf) {
   int32_t *A = tmpbuf;
-  int32_t *B = A + RESTORATION_TILEPELS_MAX;
+  int32_t *B = A + SGRPROJ_OUTBUF_SIZE;
   int8_t num[RESTORATION_TILEPELS_MAX];
   int i, j;
   // Adjusting the stride of A and B here appears to avoid bad cache effects,