pan/mdg: Always write return address to r1.w

This might not be optimal but it matches our current behaviour and is much more
justified than the "accidental" code before. Caught by the gcc warning:

../src/panfrost/midgard/midgard_schedule.c:1227:48: warning: the comparison will
always evaluate as ‘true’ for the address of ‘writeout_branch’ will never be
NULL [-Waddress]

Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18338>

src/panfrost/midgard/midgard_schedule.c

@@ -1220,11 +1220,8 @@ mir_schedule_alu(
                 predicate.no_cond = true;
         }
 
-        /* When MRT is in use, writeout loops require r1.w to be filled with a
-         * return address for the blend shader to jump to.  We always emit the
-         * move for blend shaders themselves for ABI reasons. */
-
-        if (writeout && (ctx->inputs->is_blend || ctx->writeout_branch[1])) {
+        /* Set r1.w to the return address so we can return from blend shaders */
+        if (writeout) {
                 vadd = ralloc(ctx, midgard_instruction);
                 *vadd = v_mov(~0, make_compiler_temp(ctx));