media: staging: atomisp: Fix atomisp_overlay32 compat handling

The struct atomisp_overlay contains overlay_start_x and overlay_start_y
fields. Instead of copying the value of the overlay_start_x field between
the two structs, the value of the overlay_start_y field of the compat
struct was copied to the overlay_start_x field of the 64-bit kernel struct
in get operation and back in put. The overlay_start_x field value was not
copied from or to the user space struct.

Fix this so that the value of overlay_start_x is copied to overlay_start_x
and the value of overlay_start_y is copied to overlay_start_y.

Also do copy blend_overlay_perc_u field only once.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>