i945: Consolidate common GNVS init

Change-Id: Idc3522807b17e56bdaf8f04b4bd68c6ed9777363
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/7110
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Tested-by: build bot (Jenkins)
i945: consolidate sb & nb early inits

Change-Id: I00c2c725de5b982a5e4f584b77b09017a5bc0a72
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/7062
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins)