fbdev: tridentfb: Remove the unused function shadowmode_off()

The function shadowmode_off() is defined in the tridentfb.c file, but not
called elsewhere, so delete this unused function.

drivers/video/fbdev/tridentfb.c:1131:20: warning: unused function 'shadowmode_off'.

Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=2154Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Helge Deller <deller@gmx.de>

drivers/video/fbdev/tridentfb.c

@@ -1128,11 +1128,6 @@ static inline void shadowmode_on(struct tridentfb_par *par)
 	write3CE(par, CyberControl, read3CE(par, CyberControl) | 0x81);
 }
 
-static inline void shadowmode_off(struct tridentfb_par *par)
-{
-	write3CE(par, CyberControl, read3CE(par, CyberControl) & 0x7E);
-}
-
 /* Set the hardware to the requested video mode */
 static int tridentfb_set_par(struct fb_info *info)
 {