sgi/sct.sh: support UEFI SCT tests on additional platforms

Allow UEFI SCT tests to be executed on additional platforms. This allows
executing the UEFI SCT tests as an independent test outside of ACS test
suite. Independent tests allows for selecting the tests to be executed.

Signed-off-by: Zakaria Zahi <zakaria.zahi@arm.com>
Change-Id: Ib004c2c4cfe7844891a453eba37b3806ec41f83f