video: udlfb: use true,false for bool variables

Fix the following coccicheck warning:

drivers/video/fbdev/udlfb.c:67:12-19: WARNING: Assignment of 0/1 to bool
variable
drivers/video/fbdev/udlfb.c:68:12-20: WARNING: Assignment of 0/1 to bool
variable
drivers/video/fbdev/udlfb.c:69:12-18: WARNING: Assignment of 0/1 to bool
variable
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200422071836.49123-1-yanaijie@huawei.com

drivers/video/fbdev/udlfb.c

@@ -64,9 +64,9 @@ static const struct usb_device_id id_table[] = {
 MODULE_DEVICE_TABLE(usb, id_table);
 
 /* module options */
-static bool console = 1; /* Allow fbcon to open framebuffer */
-static bool fb_defio = 1;  /* Detect mmap writes using page faults */
-static bool shadow = 1; /* Optionally disable shadow framebuffer */
+static bool console = true; /* Allow fbcon to open framebuffer */
+static bool fb_defio = true;  /* Detect mmap writes using page faults */
+static bool shadow = true; /* Optionally disable shadow framebuffer */
 static int pixel_limit; /* Optionally force a pixel resolution limit */
 
 struct dlfb_deferred_free {