Move the pr_fmt() macro to ivtv_driver.h and ensure that it
will be the first file to be included on all ivtv files.

While here, put the includes inside ivtv-driver.h on
alphabetic order.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>