distro: add rdv1mc as supported platform

Allow distro boot test on RD-V1 multi-chip platform by including the
platform name 'rdv1mc' in the list of platforms supported.

Signed-off-by: Thomas Abraham <thomas.abraham@arm.com>
Change-Id: I7dca3cee079d88c3afff2aeb7e2fedc37a40980d