cx231xx: Fix the max number of interfaces

commit 139d28826b8e2bc7a9232fde0d2f14812914f501 upstream.

The max number of interfaces was read from the wrong descriptor.

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --cc drivers/media/video/cx231xx/cx231xx-cards.c
Simple merge