Remove all checkpatch errors from codebase

Exclude stdlib files because they do not follow kernel code style.

Fixes ARM-software/tf-issues#73

Change-Id: I4cfafa38ab436f5ab22c277cb38f884346a267ab
Merge pull request #152 from jcastillo-arm/jc/tf-issues/073-v2

Remove all checkpatch errors from codebase