drm/simpledrm: Set preferred depth from format of scanout buffer

commit 9e0d493710bbeff05fc333f9641254094d1822f4 from
https://nv-tegra.nvidia.com/r/3rdparty/canonical/linux-jammy.git

 jetson_36.3

Set the preferred depth from the format of the scanout buffer. The
value cannot be hardcoded, as the scanout buffer is only known at
runtime. Also derive the fbdev emulation's bpp value from the scanout
format.

v2:
	* fix commit-message typo

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20221123115348.2521-6-tzimmermann@suse.de


(cherry picked from commit 88f19f8b)
Change-Id: I0226d75bb57acc45e31b52ba9635bcceb492afff
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/3rdparty/canonical/linux-jammy/+/2985862


Reviewed-by: svcacv <svcacv@nvidia.com>
Reviewed-by: Jonathan Hunter <jonathanh@nvidia.com>
GVS: Gerrit_Virtual_Submit <buildbot_gerritrpt@nvidia.com>
Signed-off-by: Rajeshkumar Ramasamy <rajeshkumar.ramasamy@windriver.com>