msm: camera: Parse streamon/off packet only once

Streamon/off settings should be stored in the i2c list
only once per camera open. Check in the config_dev if
streamon settings are already stored in the list and return.

Change-Id: I8ab386bdb15409b8a1dc9622262740cd956b54a0
Signed-off-by: Vivek Veenam <vveenam@codeaurora.org>
Signed-off-by: Ravi Kishore Tanuku <rktanuku@codeaurora.org>