serial: Enable Freescale 16550 workaround on arm

The same serial hardware is present on LS2080A which is arm64, and
LS1021A which is arm32, so don't limit the workaround to PPC.

Unlike PPC which uses arch/powerpc/kernel/legacy_serial.c, the ARM
targets use drivers/tty/serial/of_serial.c, so add the handle_irq
override check there as well.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/Kconfig

@@ -274,8 +274,8 @@ config SERIAL_8250_ACORN
 
 config SERIAL_8250_FSL
 	bool
-	depends on SERIAL_8250_CONSOLE && PPC_UDBG_16550
-	default PPC
+	depends on SERIAL_8250_CONSOLE
+	default PPC || ARM || ARM64
 
 config SERIAL_8250_DW
 	tristate "Support for Synopsys DesignWare 8250 quirks"

drivers/tty/serial/of_serial.c

@@ -154,6 +154,11 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
 		break;
 	}
 
+	if (IS_ENABLED(CONFIG_SERIAL_8250_FSL) &&
+	    (of_device_is_compatible(np, "fsl,ns16550") ||
+	     of_device_is_compatible(np, "fsl,16550-FIFO64")))
+		port->handle_irq = fsl8250_handle_irq;
+
 	return 0;
 out:
 	if (info->clk)