drm/plane-helper: fix uninitialized variable reference

stable inclusion
from stable-5.10.80
commit 2e548581fe5b48730d814916bd6bb8f8d8b5375a
bugzilla: 185821 https://gitee.com/openeuler/kernel/issues/I4L7CG

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2e548581fe5b48730d814916bd6bb8f8d8b5375a



--------------------------------

[ Upstream commit 7be28bd7 ]

drivers/gpu/drm/drm_plane_helper.c: In function 'drm_primary_helper_update':
drivers/gpu/drm/drm_plane_helper.c:113:32: error: 'visible' is used uninitialized [-Werror=uninitialized]
  113 |         struct drm_plane_state plane_state = {
      |                                ^~~~~~~~~~~
drivers/gpu/drm/drm_plane_helper.c:178:14: note: 'visible' was declared here
  178 |         bool visible;
      |              ^~~~~~~
cc1: all warnings being treated as errors

visible is an output, not an input. in practice this use might turn out
OK but it's still UB.

Fixes: df86af91 ("drm/plane-helper: Add drm_plane_helper_check_state()")
Reviewed-by: Simon Ser <contact@emersion.fr>
Signed-off-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca>
Signed-off-by: Simon Ser <contact@emersion.fr>
Link: https://patchwork.freedesktop.org/patch/msgid/20211007063706.305984-1-alex_y_xu@yahoo.ca


Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Reviewed-by: Weilong Chen <chenweilong@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>

Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>