sysfb: Do not include <linux/screen_info.h> from sysfb header

The header file <linux/sysfb.h> does not need anything from
<linux/screen_info.h>. Declare struct screen_info and remove
the include statements.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Sui Jingfeng <suijingfeng@loongson.cn>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230706104852.27451-4-tzimmermann@suse.de

include/linux/sysfb.h

@@ -9,7 +9,8 @@
 
 #include <linux/kernel.h>
 #include <linux/platform_data/simplefb.h>
-#include <linux/screen_info.h>
+
+struct screen_info;
 
 enum {
 	M_I17,		/* 17-Inch iMac */