video: fbdev: s1d13xxxfb: Fix kernel-doc and set but not used warnings

Fix following W=1 warnings:
- Fix set but not used variables that were used only for logging.
  Fixed by introducing no_printk() to trick compiler to think variables
  are used
- Fix kernel-doc warning by deleting an empty comment line

v3:
  - Fix grammar in commit message (Thomas)
v2:
  - Subject updated (Lee)
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Kristoffer Ericson <kristoffer.ericson@gmail.com>
Cc: Lee Jones <lee.jones@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201128224114.1033617-29-sam@ravnborg.org

drivers/video/fbdev/s1d13xxxfb.c

@@ -45,7 +45,7 @@
 #if 0
 #define dbg(fmt, args...) do { printk(KERN_INFO fmt, ## args); } while(0)
 #else
-#define dbg(fmt, args...) do { } while (0)
+#define dbg(fmt, args...) do { no_printk(KERN_INFO fmt, ## args); } while (0)
 #endif
 
 /*
@@ -512,7 +512,6 @@ s1d13xxxfb_bitblt_copyarea(struct fb_info *info, const struct fb_copyarea *area)
 }
 
 /**
- *
  *	s1d13xxxfb_bitblt_solidfill - accelerated solidfill function
  *	@info : framebuffer structure
  *	@rect : fb_fillrect structure