[acpi] Allow acpi_ioremap() to map a port I/O address

Assume that on any platforms where port I/O is used (i.e. x86), a port
I/O address may be used directly for the combined MMIO and port I/O
accessors without requiring an explicit mapping operation.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/core/acpi.c

@@ -272,6 +272,8 @@ void * acpi_ioremap ( struct acpi_address *address, size_t len ) {
 	switch ( address->type ) {
 	case ACPI_ADDRESS_TYPE_MEM:
 		return ioremap ( base, len );
+	case ACPI_ADDRESS_TYPE_IO:
+		return ( ( void * ) base );
 	default:
 		return NULL;
 	}