term/serial: Avoid double lookup of serial ports

The various functions to add a port used to return port->name, and
the callers would immediately iterate all registered ports to "find"
the one just created by comparing that return value with ... port->name.

This is a waste of cycles and code. Instead, have those functions
return "port" directly.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

grub-core/term/ieee1275/serial.c

@@ -217,7 +217,7 @@ dev_iterate (struct grub_ieee1275_devalias *alias)
   return 0;
 }
 
-static const char *
+static struct grub_serial_port *
 add_port (struct ofserial_hash_ent *ent)
 {
   struct grub_serial_port *port;
@@ -245,10 +245,10 @@ add_port (struct ofserial_hash_ent *ent)
 
   grub_serial_register (port);
 
-  return port->name;
+  return port;
 }
 
-const char *
+const struct grub_serial_port *
 grub_ofserial_add_port (const char *path)
 {
   struct ofserial_hash_ent *ent;