Fix 9ce1626b: Some blitters have bp->remap aliased to remap for performance. (#11626)

While this probably doesn't make a huge difference for the custom transparent remap code path, the alias is there so use it.

src/blitter/32bpp_sse_func.hpp

@@ -396,7 +396,7 @@ bmcr_alpha_blend_single:
 				/* Apply custom transparency remap. */
 				for (uint x = (uint) bp->width; x > 0; x--) {
 					if (src->a != 0) {
-						*dst = this->LookupColourInPalette(bp->remap[GetNearestColourIndex(*dst)]);
+						*dst = this->LookupColourInPalette(remap[GetNearestColourIndex(*dst)]);
 					}
 					src_mv++;
 					dst++;