media: staging: rkisp1: params: no need to lock default config

In the function 'rkisp1_params_config_parameter' the lock
is taken while applying the default config. But the lock
only needs to protect the buffers list and the 'is_streaming'
field, so move the locking to lock only what is needed.

Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Acked-by: Helen Koike <helen.koike@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>