powerpc/embedded6xx: Remove unused functions holly_power_off and holly_halt

Silence the following warnings triggered using W=1:

  arch/powerpc/platforms/embedded6xx/holly.c:236:6: error: no previous prototype for 'holly_power_off'
  arch/powerpc/platforms/embedded6xx/holly.c:243:6: error: no previous prototype for 'holly_halt'
Signed-off-by: NMathieu Malaterre <malat@debian.org>
Reviewed-by: NMukesh Ojha <mojha@codeaurora.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/embedded6xx/holly.c

@@ -234,18 +234,6 @@ static void __noreturn holly_restart(char *cmd)
 	for (;;) ;
 }
 
-void holly_power_off(void)
-{
-	local_irq_disable();
-	/* No way to shut power off with software */
-	for (;;) ;
-}
-
-void holly_halt(void)
-{
-	holly_power_off();
-}
-
 /*
  * Called very early, device-tree isn't unflattened
  */