Log error handling prior to module initialisation

The purpose of this change is to include a checks when reading registers for printing logs. This is covered in both PL011, where it will now ensure the module is initialised prior to attempting to print characters, and also in GTimer, where it will ensure the module needs to be initialised before attempting to read the timestamp related registers from the configuration.

This means that if any attempts are made before memory set-up is complete, the system will handle this.

Signed-off-by: Katherine Vincent katherine.vincent@arm.com Change-Id: I0d22ffbe6e4aaa7ad3b229848705e8ca77e7d475