[media] si2165: fix sparse warning

drivers/media/dvb-frontends/si2165.c:329:16: warning: odd constant _Bool cast (ffffffffffffffea becomes 1)

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