configs/rdv1mc: change configurations based on the host architecture

Change the build configurations of RD-V1-MC based on the host machine
architecture. Environment variable BUILD_MACHINE_ARCH is used for host
specific changes in the configuration.

Signed-off-by: Tony Nadackal <tony.nadackal@arm.com>
Change-Id: I0b921dd187dece840eb2723d0d95e22b35a0c030