linux-phytec-fsl

drm/rockchip: Convert psr_list_mutex to spinlock and use it

This patch converts the psr_list_mutex to a spinlock and locks
all access to psr_list to avoid races (however unlikely they
were).

Reviewed-by: Yakir Yang <ykk@rock-chips.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>