Fix warning about bitwise 'not' on boolean

Change-Id: I4732dbbb71a0db9ac284a4b2ae5f10816e0e9264

av1/common/av1_loopfilter.c

diff --git a/av1/common/av1_loopfilter.c b/av1/common/av1_loopfilter.c
index 33a6d6a..6dc58c1 100644
--- a/av1/common/av1_loopfilter.c
+++ b/av1/common/av1_loopfilter.c
@@ -2420,7 +2420,7 @@
                                       &col_masks);
 
     // Disable filtering on the leftmost column or tile boundary
-    unsigned int border_mask = ~(mi_col == 0);
+    unsigned int border_mask = ~(mi_col == 0 ? 1 : 0);
 #if CONFIG_LOOPFILTERING_ACROSS_TILES
     MODE_INFO *const mi = cm->mi + (mi_row + idx_r) * cm->mi_stride + mi_col;
     if (av1_disable_loopfilter_on_tile_boundary(cm) &&