auxdisplay: constify charlcd_ops.

charlcd_ops are not supposed to change at runtime. All functions
working with charlcd_ops provided by <misc/charlcd.h> work with
const charlcd_ops. So mark the non-const structs as const.

File size before:
text data bss dec hex filename
12750 560 362 13672 3568 drivers/auxdisplay/panel.o

File size After adding 'const':
text data bss dec hex filename
12942 368 362 13672 3568 drivers/auxdisplay/panel.o

Signed-off-by: Arvind Yadav <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/auxdisplay/panel.c

···
 	spin_unlock_irq(&pprt_lock);
 }
 
-static struct charlcd_ops charlcd_serial_ops = {
+static const struct charlcd_ops charlcd_serial_ops = {
 	.write_cmd	= lcd_write_cmd_s,
 	.write_data	= lcd_write_data_s,
 	.clear_fast	= lcd_clear_fast_s,
 	.backlight	= lcd_backlight,
 };
 
-static struct charlcd_ops charlcd_parallel_ops = {
+static const struct charlcd_ops charlcd_parallel_ops = {
 	.write_cmd	= lcd_write_cmd_p8,
 	.write_data	= lcd_write_data_p8,
 	.clear_fast	= lcd_clear_fast_p8,
 	.backlight	= lcd_backlight,
 };
 
-static struct charlcd_ops charlcd_tilcd_ops = {
+static const struct charlcd_ops charlcd_tilcd_ops = {
 	.write_cmd	= lcd_write_cmd_tilcd,
 	.write_data	= lcd_write_data_tilcd,
 	.clear_fast	= lcd_clear_fast_tilcd,