net: mana: Support hibernation and kexec

Implement the suspend/resume/shutdown callbacks for hibernation/kexec.

Add mana_gd_setup() and mana_gd_cleanup() for some common code, and
use them in the mand_gd_* callbacks.

Reuse mana_probe/remove() for the hibernation path.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>