V4L: pvrusb2: Handle larger cx2341x firmware images

V4L: pvrusb2: Handle larger cx2341x firmware images

Rework the cx23416 firmware loader so that it longer requires the
firmware size to be a multiple of 8KB.  Until recently all cx2341x
firmware images were exactly 256KB, but newer firmware is larger than
that and also appears to have arbitrary size.  We still must check
against a multiple of 4 bytes (because the cx23416 itself uses a 32
bit word size).

This fix is already in the upstream driver source and has proven
itself there; this is a backport for the 2.6.20.y kernel series.

(backported from commit 90060d32ca0a941b158994f78e60d0381871c84b)

Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>