docs: clarify multiple UUID support in ffa manifest

If a partition supports multiple UUID, the UUID property in the list
of partition properties in the FF-A manifest must be a list or array.
Update the document to clarify the same.

Change-Id: Id13fe8dbf57a00e5cd186158270b716a4a9aedf7
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
1 file changed