video: fbdev: omapfb: panel-dsi-cm: Use sysfs_emit() instead of snprintf()

[ Upstream commit f63658a59c3d439c8ad7b290f8ec270980e0f384 ]

Use sysfs_emit instead of scnprintf, snprintf or sprintf.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Jing Yao <yao.jing2@zte.com.cn>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>