media: rc/ite-cir: fix smatch warning

Use sizeof instead of ARRAY_SIZE to fix this smatch warning:

drivers/media/rc/ite-cir.c:385 ite_tx_ir() warn: calling memset(x, y, ARRAY_SIZE());

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>