[media] Don't export format_by_forcc on two different drivers

Drivers should append their name on exported symbols, to avoid
conflicts with allyesconfig:

drivers/staging/built-in.o: In function `format_by_fourcc':
/home/v4l/work_trees/linus/drivers/staging/cx25821/cx25821-video.c:96: multiple definition of `format_by_fourcc'
drivers/media/built-in.o:/home/v4l/work_trees/linus/drivers/media/common/saa7146_video.c:88: first defined here

Let's rename both occurences with a small shellscript:

for i in drivers/staging/cx25821/*.[ch]; do sed s,format_by_fourcc,cx25821_format_by_fourcc,g <$i >a && mv a $i; done
for i in drivers/media/common/saa7146*.[ch]; do sed s,format_by_fourcc,saa7146_format_by_fourcc,g <$i >a && mv a $i; done
for i in include/media/saa7146*.[ch]; do sed s,format_by_fourcc,saa7146_format_by_fourcc,g <$i >a && mv a $i; done

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>