media: amphion: release core lock before reset vpu core

In reset vpu core, driver will wait for a response event,
but if there are still some events unhandled,
they will be handled first, driver may acquire core lock for that.
So if we do reset in core lock, it may led to reset timeout.

Fixes: 9f599f35

 ("media: amphion: add vpu core driver")
Signed-off-by: Ming Qian <ming.qian@nxp.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>