msm: camera: crm: increasing mutex lock window

Serializing the complete call to avoid list corruption.
Before complete if flush gets called second time, it will
reinitialize wait queue.

Change-Id: Ia4f5865d52da26e5bd18218b83d19724412aa1f5
Signed-off-by: Alok Pandey <akumarpa@codeaurora.org>