serial: 8250_dw: Add missing MODULE_ALIAS() for module autoloading support

Without this the module does not load automatically whenever suitable
platform device appears.
Reported-by: Jerome Blin <jerome.blin@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_dw.c

@@ -608,3 +608,4 @@ module_platform_driver(dw8250_platform_driver);
 MODULE_AUTHOR("Jamie Iles");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Synopsys DesignWare 8250 serial port driver");
+MODULE_ALIAS("platform:dw-apb-uart");