slimbus: core: do not call device_status under a lock

Calling device_status callback under a lock would prevent drivers
to do any slimbus trasactions which would invoke this lock like
get_laddr(). Remove this unnecessary lock!

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>