signature: disable SMIMECapabilities information in the bundle signature
signature: disable SMIMECapabilities information in the bundle signature

This information is not needed for our use-case and removing it saves ~100
bytes.

Signed-off-by: Jan Luebbe <3a82f1ac4ad59607a20f180f1c67ac8ba31ad0d5@pengutronix.de>

rauc/rauc,jluebbe/rauc,rauc/rauc,jluebbe/rauc,ejoerns/rauc,ejoerns/rauc,rauc/rauc,ejoerns/rauc,jluebbe/rauc