auxdisplay: cfag12864bfb: remove superfluous header files

cfag12864bfb.c doesn't use any macro or function declared in
linux/delay.h, linux/string.h and linux/uaccess.h. Thus,
these files can be removed from cfag12864bfb.c safely without
affecting the compilation.

Signed-off-by: Mianhan Liu <liumh1@shanghaitech.edu.cn>
[reworded]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

drivers/auxdisplay/cfag12864bfb.c

@@ -12,13 +12,10 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
-#include <linux/delay.h>
 #include <linux/errno.h>
 #include <linux/fb.h>
 #include <linux/mm.h>
 #include <linux/platform_device.h>
-#include <linux/string.h>
-#include <linux/uaccess.h>
 #include <linux/cfag12864b.h>
 
 #define CFAG12864BFB_NAME "cfag12864bfb"