drm/amd/display: Extend dc_plane_get_status with flags

drm/amd/display: Extend dc_plane_get_status with flags

[WHY]
dc_plane_get_status may be used for reading other plane properties
in the future.

[HOW]
Provide API for choosing plane properties to read.

Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Reviewed-by: Aric Cyr <aric.cyr@amd.com>
Reviewed-by: Swapnil Patel <swapnil.patel@amd.com>
Signed-off-by: Tomasz Siemek <Tomasz.Siemek@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>