V4L/DVB (5942): Usb/vp7045.c: ARRAY_SIZE()

This patch replaces an array size calculation done using sizeof
with an invocation of the ARRAY_SIZE macro.

Tested by compilation on an i386 box using "allyesconfig".
Diffed against Linus' git-tree.

Signed-off-by: Andi Drebes <lists-receive@programmierforen.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>