media: allegro-dvt: avoid EN DASH char

While there's nothing wrong with EN DASH on C code, this probably
came from some cut-and paste from an ITU-T table.
It sounds better to just an HYPHEN here.

Reviewed-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>