[media] [V2,02/24] pci/saa7134/saa7134.h: use IS_ENABLED() macro

replace:
 #if defined(CONFIG_VIDEO_SAA7134_DVB) || \
     defined(CONFIG_VIDEO_SAA7134_DVB_MODULE)
with:
 #if IS_ENABLED(CONFIG_VIDEO_SAA7134_DVB)
This change was made for: CONFIG_VIDEO_SAA7134_DVB

Reported-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>