fix(gpt): unify logging messages

This patch modifies GPT library comments and makes
logging messages consistent with PRIx64 usage and
TF-A format used in other modules.
Minor changes are made to make the code compliant
with MISRA C requirements.

Change-Id: Ic40e1b7ac43cd9602819698d00e1ce3a8c7183ce
Signed-off-by: AlexeiFedorov <Alexei.Fedorov@arm.com>
2 files changed