media: mtk-vpu: Fix a resource leak in the error handling path of 'mtk_vpu_probe()'

[ Upstream commit 2143ad413c05c7be24c3a92760e367b7f6aaac92 ]

A successful 'clk_prepare()' call should be balanced by a corresponding
'clk_unprepare()' call in the error handling path of the probe, as already
done in the remove function.

Update the error handling path accordingly.

Fixes: 3003a180 ("[media] VPU: mediatek: support Mediatek VPU")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Houlong Wei <houlong.wei@mediatek.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>