media: af9035: fix broken I2C and USB I/O

commit 9323297dc0ea9141f8099e474657391bb3ad98f8 upstream.

There was three small buffer len calculation bugs which caused
driver non-working. These are coming from recent commit:
commit 7760e148350bf6df95662bc0db3734e9d991cb03
[media] af9035: Don't use dynamic static allocation

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>