Silicon/Marvell: add VariablePolicy resolutions

Add resolutions for
- VariablePolicyLib
- VariablePolicyHelperLib
- VariablePolicyLib (DXE_RUNTIME_DRIVER)

These need SafeIntLib, so move that out of the ifdef restricting it to
capsule builds.

Cc: Marcin Wojtas <mw@semihalf.com>
Signed-off-by: Leif Lindholm <leif@nuviainc.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>