feat(lib/rmm_el3_ifc): get console info from EL3

This patch relies on Boot Manifest v0.3 being implemented at EL3.
The FVP now dynamically initializes the console info received from
EL3.

Signed-off-by: Harry Moulton <harry.moulton@arm.com>
Signed-off-by: Soby Mathew <soby.mathew@arm.com>
Change-Id: I6d51c1bf5cc04e4828770829305039c7a1854604