Platform/Sgi: Add platform error handling driver

Driver to install the ACPI tables required to enable platform error
handling on RD platforms. ACPI table helper functions are also
implemented by the driver.

Signed-off-by: Omkar Anand Kulkarni <omkar.kulkarni@arm.com>
Change-Id: Ibdf6bd9f5efc44ef226bebbd677b689f196e846b