media: allegro-dvt: fix build failure

nal-h264.h is a local header, not a global one. Use "" instead of <>.

Fixed this compile error:

  CC      drivers/staging/media/allegro-dvt/nal-h264.o
drivers/staging/media/allegro-dvt/nal-h264.c:24:10: fatal error: nal-h264.h: No such file or directory
 #include <nal-h264.h>
          ^~~~~~~~~~~~

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>