msm: camera: ope: Move request id validity check outside of lock

In some corner cases, flush request and cdm callback can
run in parallel. This may lead to data curruption in cdm
callback if bl request gets freed by flush.

As lock is also part of corrupted data structure hence move
the request validity check outside of lock in cdm callback
to prevent this issue.

CRs-Fixed: 2615308
Change-Id: I2b166eb491e394000a63d0fe4e6d001ba3ddef76
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>