media: dvb: add return value check on Write16

Write16 can return an error code -1 when the i2c_write fails. The
fix checks for these failures and returns the error upstream

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