camera_v2: Use JPEG_DBG instead of JPEG_ERR for some messages

Avoid printing by default a number of debug messages, to decrease
the ioctl latency in the dual JPEG use case.

Signed-off-by: Kamen Kirov <kkirov@codeaurora.org>
Change-Id: I1cfd16270282587cbf1821d34f658af80fe69fd1