Add checks for unsupported smm variable features

Checks added to defend against a client requesting
unsupported features when setting a UEFI variable. For
example, an attempt to set an unsupported variable
attribute will result in EFI_UNSUPPORTED being returned.

Signed-off-by: Julian Hall <julian.hall@arm.com>
Change-Id: If9478e6924ed9356b363460b164655339655236a
2 files changed