[efi] Try various possible SNP receive filters

[efi] Try various possible SNP receive filters

The behavior observed in the Apple EFI (1.10) RecieveFilters() call
is:

  - failure if any of the PROMISCUOUS or MULTICAST filters are
    included

  - success if only UNICAST is included, however the result is
    UNICAST|BROADCAST

  - success if only UNICAST and BROADCAST are included

  - if UNICAST, or UNICAST|BROADCAST are used, but the previous call
    tried (and failed) to set UNICAST|BROADCAST|MULTICAST, then the
    result is UNICAST|BROADCAST|MULTICAST

Work around this apparently broken SNP implementation by trying
RecieveFilterMask, then falling back to UNICAST|BROADCAST|MULTICAST,
then UNICAST|BROADCAST, and finally UNICAST.

Modified-by: Michael Brown <mcb30@ipxe.org>
Tested-by: Curtis Larsen <larsen@dixie.edu>
Signed-off-by: Michael Brown <mcb30@ipxe.org>