fbdev: imxfb: warn about invalid left/right margin

stable inclusion
from stable-v5.10.188
commit 7041605e8594c41149e69222f8a42250cc42d2ef
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8KYFP

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7041605e8594c41149e69222f8a42250cc42d2ef



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[ Upstream commit 4e47382f ]

Warn about invalid var->left_margin or var->right_margin. Their values
are read from the device tree.

We store var->left_margin-3 and var->right_margin-1 in register
fields. These fields should be >= 0.

Fixes: 7e8549bc ("imxfb: Fix margin settings")
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>