drm/atomic-helper: Change parameter name of crtc_set_mode()

crtc_set_mode() deals with calling the modeset related hooks for CRTC,
connectors and bridges if and when a new commit changes them. It takes
the drm_atomic_state being committed as a parameter.

However, that parameter name is called as old_state, which is pretty
confusing. Let's rename that variable as state.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20250213-bridge-connector-v3-15-e71598f49c8f@kernel.org


Signed-off-by: Maxime Ripard <mripard@kernel.org>