drm/vc4: hdmi: Don't access the connector state in reset if kmalloc fails

stable inclusion
from stable-v5.10.137
commit c015d12317c503dff7fc8f20a6ae00be255cb1a3
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I60PLB

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c015d12317c503dff7fc8f20a6ae00be255cb1a3



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[ Upstream commit e55a0775 ]

drm_atomic_helper_connector_reset uses kmalloc which, from an API
standpoint, can fail, and thus setting connector->state to NULL.
However, our reset hook then calls drm_atomic_helper_connector_tv_reset
that will access connector->state without checking if it's a valid
pointer or not.

Make sure we don't end up accessing a NULL pointer.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Suggested-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20201215154243.540115-5-maxime@cerno.tech


Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>