MdeModulePkg: consider UNSUPPORTED return as valid in ArmFfaStandaloneMmLib

commit b534cabbdac4 ("ArmFfaLib: Add Rx/Tx support for Stmm secure partition")
makes ArmFfaStandlaoneMm(Core)Lib map Rx/Tx buffer in its constructor.

This makes a failure of loading StandaloneMm in legacy platform
which doesn't implements Rx/Tx buffer related API since it doesn't need to.

StandaloneMm could be only service provider not cosumer in some platform
where doesn't need to map RxTx buffer.
Therefore, Considier EFI_UNSUPPORTED return in ArmFfaStandaloneMmLib's
constructor.

Fixes: b534cabbdac4 ("ArmFfaLib: Add Rx/Tx support for Stmm secure partition")
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
1 file changed