media: gspca: Check the return value of write_bridge for timeout

In po1030_probe(), m5602_write_bridge() can timeout and return an error
value. The fix checks for the return value and propagates upstream
consistent with other usb drivers.

Signed-off-by: Aditya Pakki <pakki001@umn.edu>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>