drm/atomic-helper: Fix spelling mistake "preceeding" -> "preceding"

There is a typo in the kernel documentation for function
drm_atomic_helper_wait_for_dependencies. Fix it.

Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231027024459.12793-1-chentao@kylinos.cn