rdv3r1: configure I/O stream for lcpfw

Configure the macros FMW_IO_STDIN_ID and FWM_IO_STDOUT_ID exposed by the
I/O framework to set the LCP UART as the system entity responsible for
handling I/O for the mcp firmware.

Signed-off-by: Shriram K <shriram.k@arm.com>
Signed-off-by: Nancy . <nancy@arm.com>
Change-Id: I8316a40d50cd89b7d861f86db5d7aa5641401952