[media] media: v4l2-core: v4l2-dv-timings.c: Cleaning up code wrong value used in aspect ratio

Wrong value used in same cases for the aspect ratio.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Acked-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Cc: stable@vger.kernel.org      # for v3.12 and up
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>