r600/sb: insert the else clause when we might depart from a loop

If there is a break inside the else clause and this means we
are breaking from a loop, the loop finalise will want to insert
the LOOP_BREAK/CONTINUE instruction, however if we don't emit
the else there is no where for these to end up, so they will end
up in the wrong place.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101442


Tested-By: Gert Wollny <gw.fossdev@gmail.com>
Cc: <mesa-stable@lists.freedesktop.org>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
(cherry picked from commit 8d633f06)