drm/amd/display: Clear HDMI HPD pending work only if it is enabled

drm/amd/display: Clear HDMI HPD pending work only if it is enabled

[Why&How]
On amdgpu_dm_connector_destroy(), the driver attempts to cancel pending
HDMI HPD work without checking if the HDMI HPD is enabled.

Added a check that it is enabled before clearing it.

Fixes: 6a681cd90345 ("drm/amd/display: Add an hdmi_hpd_debounce_delay_ms module")
Signed-off-by: Ivan Lipski <ivan.lipski@amd.com>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>