[media] radio-tea5764: fix sparse warnings

drivers/media/radio/radio-tea5764.c:168:24: warning: cast to restricted __be16
drivers/media/radio/radio-tea5764.c:168:24: warning: cast to restricted __be16
drivers/media/radio/radio-tea5764.c:168:24: warning: cast to restricted __be16
drivers/media/radio/radio-tea5764.c:168:24: warning: cast to restricted __be16
drivers/media/radio/radio-tea5764.c:185:20: warning: incorrect type in assignment (different base types)
drivers/media/radio/radio-tea5764.c:186:20: warning: incorrect type in assignment (different base types)
drivers/media/radio/radio-tea5764.c:187:20: warning: incorrect type in assignment (different base types)
drivers/media/radio/radio-tea5764.c:188:20: warning: incorrect type in assignment (different base types)
drivers/media/radio/radio-tea5764.c:189:20: warning: incorrect type in assignment (different base types)

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>