ACPI: Drop typedef global_nvs_t

Bring all GNVS related initialisation function to global
scope to force identical signatures. Followup work is
likely to remove some as duplicates.

Change-Id: Id4299c41d79c228f3d35bc7cb9bf427ce1e82ba1
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42489
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/southbridge/intel/lynxpoint/serialio.c

@@ -205,7 +205,7 @@ static void serialio_init(struct device *dev)
 	}
 
 	if (config->sio_acpi_mode) {
-		global_nvs_t *gnvs;
+		struct global_nvs *gnvs;
 
 		/* Find ACPI NVS to update BARs */
 		gnvs = acpi_get_gnvs();