fbdev: omapfb: lcd_mipid: Fix an error handling path in mipid_spi_probe()

[ Upstream commit 79a3908d1ea6c35157a6d907b1a9d8ec06015e7a ]

If 'mipid_detect()' fails, we must free 'md' to avoid a memory leak.

Fixes: 66d2f99d ("omapfb: add support for MIPI-DCS compatible LCDs")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>