serial: pxa: Staticize local symbols

These local symbols are used only in this file.
Fix the following sparse warnings:

drivers/tty/serial/pxa.c:793:17: warning: symbol 'serial_pxa_pops' was not declared. Should it be static?
drivers/tty/serial/pxa.c:971:12: warning: symbol 'serial_pxa_init' was not declared. Should it be static?
drivers/tty/serial/pxa.c:986:13: warning: symbol 'serial_pxa_exit' was not declared. Should it be static?
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/pxa.c

@@ -765,7 +765,7 @@ static struct console serial_pxa_console = {
 #define PXA_CONSOLE	NULL
 #endif
 
-struct uart_ops serial_pxa_pops = {
+static struct uart_ops serial_pxa_pops = {
 	.tx_empty	= serial_pxa_tx_empty,
 	.set_mctrl	= serial_pxa_set_mctrl,
 	.get_mctrl	= serial_pxa_get_mctrl,
@@ -943,7 +943,7 @@ static struct platform_driver serial_pxa_driver = {
 	},
 };
 
-int __init serial_pxa_init(void)
+static int __init serial_pxa_init(void)
 {
 	int ret;
 
@@ -958,7 +958,7 @@ int __init serial_pxa_init(void)
 	return ret;
 }
 
-void __exit serial_pxa_exit(void)
+static void __exit serial_pxa_exit(void)
 {
 	platform_driver_unregister(&serial_pxa_driver);
 	uart_unregister_driver(&serial_pxa_reg);