msm: camera: reqmgr: Add checks before reporting the error

Add the null check for dev parameter before reporting the error on
link. Certain corner scenario for flash, send request return native
value in that case dev parameter could be null.

CRs-Fixed: 2814597
Change-Id: Ibe08f12c2f2c1864c46b17b0ae0f8df5c5648d35
Signed-off-by: Ravikishore Pampana <rpampana@codeaurora.org>