pan/mdg: Always write return address to r1.w (+ a midgard print fix)

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