rdv3r1: add platform module for lcpfw

Add an initial implementation of the LCP platform module that indicates
the completion of the LCP RAM boot stage. This module is expected to get
additional functionality in subsequent additions to the LCP RAM
firmware.

Signed-off-by: Shriram K <shriram.k@arm.com>
Signed-off-by: Nancy . <nancy@arm.com>
Change-Id: I5ba37189ba7e5d8c9aaf6928f9e2312e5072e44f