Platform/Sgi: Route logs to different sets of consoles

Route secure (from secure partition) and non-secure console messages
to different sets of UART console ports. This aligns with the security
state the PE is in when logs are put out. In addition, this allows
consolidation of UART related macros across all the variants of
Neoverse reference design platforms.

Signed-off-by: Rohit Mathew <rohit.mathew@arm.com>
Reviewed-by: Thomas Abraham <thomas.abraham@arm.com>