[media] ad9389b: remove rx-sense irq dependency

Removed dependency on rx-sense interrupt, it's a leftover from obsolete
code. Removing this simplifies the code.

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