V4L/DVB (12557): Use C99 comment CodingStyle

The ir-keymaps.c has frequent additions. As people tend to copy an old
keyboard entry, a bad CodingStyle at an ancient entry may result on a
freshly bad CodingStyle patch.

So, better to fix the CodingStyle for the entire file.

This patch is the first of a series of patches fixing it, generated by
some perl magic plus manual handling.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>