CHROMIUM: [media] rk3288-vpu: Make find_format() use fourcc directly

CHROMIUM: [media] rk3288-vpu: Make find_format() use fourcc directly

As a prerequisite for using find_format() helpers from contexts in which
a v4l2_format struct is not available, this patch makes it take u32 fourcc
as its argument instead, since it was the only member of that struct it
actually used anyway.

BUG=chromium:485409
TEST=vda/veatests, Chrome with crrev.com/1097913002.

Signed-off-by: Tomasz Figa <tfiga@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/269866
Reviewed-by: Pawel Osciak <posciak@chromium.org>
Trybot-Ready: Pawel Osciak <posciak@chromium.org>

Change-Id: Ifa9c4e3e378fbeafb6453a01b9e4f7c11606025b
Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Signed-off-by: Yakir Yang <ykk@rock-chips.com>