media: rcar_drif: fix a memory disclosure

media: rcar_drif: fix a memory disclosure

BugLink: https://bugs.launchpad.net/bugs/1858428
[ Upstream commit d39083234c60519724c6ed59509a2129fd2aed41 ]

"f->fmt.sdr.reserved" is uninitialized. As other peer drivers
like msi2500 and airspy do, the fix initializes it to avoid
memory disclosures.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>