Main fixes:

Remove unused type conversion

Fix invalid use of function pointer [Rule 1.3]

Fix variable essential type doesn't match [Rule 10.3]

Voided non c-library functions whose return types are not used
 [Rule 17.7]

Change-Id: I23994c9d4d6a240080933d848d2b03865acaa833
Signed-off-by: Anthony Zhou <anzhou@nvidia.com>