[media] solo6x10: Fix solo_eeprom_read retval type

s/unsigned short/u16/

Signed-off-by: Ismael Luceno <ismael@iodev.co.uk>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>