HID: picoLCD: Constify lcd_ops

'struct lcd_ops' is not modified by core backlight code, so it can be
made const for increased code safety.

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Reviewed-by: Bruno Prémont <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Lee Jones <[e-mail]>

drivers/hid/hid-picolcd_lcd.c

···
 	return fb && fb == picolcd_fbinfo((struct picolcd_data *)lcd_get_data(ldev));
 }
 
-static struct lcd_ops picolcd_lcdops = {
+static const struct lcd_ops picolcd_lcdops = {
 	.get_contrast   = picolcd_get_contrast,
 	.set_contrast   = picolcd_set_contrast,
 	.check_fb       = picolcd_check_lcd_fb,