Silicon/SynQuacer/NetsecDxe: avoid media detection delay at boot

Instead of unconditionally delaying the boot up to 5 seconds, even
if no network cable is connected in the first place, provide an
implementation of the EFI adapter information protocol so that the
upper networking layers can wait gracefully for the link to come up,
but only when the network is actually used to boot from.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>