feat(el3-spmc): make platform logical partition optional

Prior to this commit a logical platform specific partition is added when
compiling with SPMC at EL3. Not all platform need to add a logical
platform so make this optional.

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Change-Id: I3bdd2a91350330c1637e8d84765974bfb6b225d7
1 file changed