drm: panel: Fix bpc for OrtusTech COM43H4M85ULC panel

drm: panel: Fix bpc for OrtusTech COM43H4M85ULC panel

BugLink: https://bugs.launchpad.net/bugs/1902115
[ Upstream commit 3b8095169982ff4ec2a1b4be61b7224bbef23b48 ]

The OrtusTech COM43H4M85ULC panel is a 18-bit RGB panel. Commit
f098f168e91c ("drm: panel: Fix bus format for OrtusTech COM43H4M85ULC
panel") has fixed the bus formats, but forgot to address the bpc value.
Set it to 6.

Fixes: f098f168e91c ("drm: panel: Fix bus format for OrtusTech COM43H4M85ULC panel")
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200824003254.21904-1-laurent.pinchart@ideasonboard.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Ian May <ian.may@canonical.com>