media: gspca: properly check for errors in po1030_probe()

If m5602_write_sensor() or m5602_write_bridge() fail, do not continue to
initialize the device but return the error to the calling funtion.

Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Link: https://lore.kernel.org/r/20210503115736.2104747-64-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>