EmbeddedPkg: Unload image on EFI_SECURITY_VIOLATION

EmbeddedPkg: Unload image on EFI_SECURITY_VIOLATION

For the LoadImage() boot service, with EFI_SECURITY_VIOLATION retval,
the Image was loaded and an ImageHandle was created with a valid
EFI_LOADED_IMAGE_PROTOCOL, but the image can not be started right now.
This follows UEFI Spec.

But if the caller of LoadImage() doesn't have the option to defer
the execution of an image, we can not treat EFI_SECURITY_VIOLATION
like any other LoadImage() error, we should unload image for the
EFI_SECURITY_VIOLATION to avoid resource leak.

This patch is to do error handling for EFI_SECURITY_VIOLATION explicitly
for the callers in EmbeddedPkg which don't have the policy to defer the
execution of the image.

Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Philippe Mathieu-Daude <philmd@redhat.com>
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1992
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>