Fix the null dereferenced issues from converity scan results.
issue id:
  3618300:Dereference after null check
  3618364:Dereference after null check
  3618463:Dereference after null check
  3618470:Explicit null dereferenced
  3618520:Dereference after null check

Test: issue fixed by converity scan.

Change-Id: I577ed094a1f9b493de61b84827c0e1157a4fbd2f
Signed-off-by: Luo Ji <ji.luo@nxp.com>