ARM: shmobile: Remove unused declaration of r8a7778_add_standard_devices_dt()

The actual implementation was removed by commit 40216263 ("ARM:
shmobile: Remove unused r8a7778 auxdata and callback") in v3.12.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

arch/arm/mach-shmobile/r8a7778.h

@@ -63,7 +63,6 @@ enum {
 };
 
 extern void r8a7778_add_standard_devices(void);
-extern void r8a7778_add_standard_devices_dt(void);
 extern void r8a7778_add_dt_devices(void);
 
 extern void r8a7778_init_late(void);