drm/atmel-hlcdc: destroy properly the plane state in the reset callback

drm/atmel-hlcdc: destroy properly the plane state in the reset callback

If there is a plane state to destroy when doing a plane reset, destroy
it using the atmel_hlcdc_plane_destroy_state() function. So we call
__drm_atomic_helper_plane_destroy_state() and avoid code duplication.

Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Reviewed-by: Manikandan Muralidharan <manikandan.m@microchip.com>
Link: https://patch.msgid.link/20251218-lcd_cleanup_mainline-v2-8-df837aba878f@microchip.com
Signed-off-by: Manikandan Muralidharan <manikandan.m@microchip.com>