openrisc: Remove unused declaration of __initramfs_start

Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NJonas Bonn <jonas@southpole.se>

arch/openrisc/kernel/vmlinux.h

@@ -3,7 +3,6 @@
 
 #ifdef CONFIG_BLK_DEV_INITRD
 extern char __initrd_start, __initrd_end;
-extern char __initramfs_start;
 #endif
 
 extern u32 __dtb_start[];