drm: radeon: *_cs_packet_parse_vline() cleanup

Simplify the way the return value is set a number of times (mostly on
error).

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --cc drivers/gpu/drm/radeon/evergreen_cs.c
Simple merge

diff --cc drivers/gpu/drm/radeon/r100.c
Simple merge

diff --cc drivers/gpu/drm/radeon/r600_cs.c
Simple merge