drm/panthor: return error on truncated firmware

drm/panthor: return error on truncated firmware

panthor_fw_load() detects truncated firmware images, but jumps to the
common cleanup path without setting ret. If no previous error was recorded,
the function can return 0 and treat the invalid firmware as successfully
loaded.

Set ret to -EINVAL before leaving the truncated-image path.

Fixes: 2718d91816ee ("drm/panthor: Add the FW logical block")
Cc: stable@vger.kernel.org
Signed-off-by: Osama Abdelkader <osama.abdelkader@gmail.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://patch.msgid.link/20260714163056.22329-1-osama.abdelkader@gmail.com
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>