[media] staging: media: bcm2048: radio-bcm2048.c - removed IRQF_DISABLED macro

- this patch removes IRQF_DISABLED macro, as this is
  deprecated/noop.

Signed-off-by: Anil Belur <askb23@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>