V4L/DVB (4595): Remove CONFIG_VIDEO_PVRUSB2_24XXX from pvrusb2 driver

Support for 24xxx devices was previously explicitly bracketed with
CONFIG_VIDEO_PVRUSB2_24XXX inside the code because we didn't trust the
stability of these changes.  We trust it now; so there's no reason to
leave this out of the driver anymore.

Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>