media: ov2740: allow OTP data access during streaming

OTP data access of ov2740 need enable the streaming mode to load
and it could be done in any time, so driver need allow the OTP
data access during streaming instead of return EBUSY, this patch
try to read the OTP data out in STREAMON if OTP data is not ready
before first time streaming start.

Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
Signed-off-by: Qingwu Zhang <qingwu.zhang@intel.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>