V4L/DVB (9520): stb0899 Remove double .read_status assignment

Currently in stb0899 code  it appears double .read_status assignment
Send patch to fix it.

Cc: Manu Abraham <abraham.manu@gmail.com>
Signed-off-by: Igor M. Liplianin <liplianin@me.by>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>