[ARM] 2944/1: GCC 4 mx1ads serial driver compile fix

Patch from Vincent Sanders

When building the mx1ads ARM platforms the serial driver fails to compile
with GCC 4.01 due to extern/static ambiguity.
Signed-off-by: NVincent Sanders <vince@arm.linux.org.uk>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

drivers/serial/imx.c

@@ -860,7 +860,7 @@ imx_console_setup(struct console *co, char *options)
 	return uart_set_options(&sport->port, co, baud, parity, bits, flow);
 }
 
-extern struct uart_driver imx_reg;
+static struct uart_driver imx_reg;
 static struct console imx_console = {
 	.name		= "ttySMX",
 	.write		= imx_console_write,