ipmi: fix return from atca_oem_poweroff_hook

A void returning function returned the return value of another void
returning function...

Spotted by sparse.

Signed-off-by: Adrian Bunk <[e-mail]>
Signed-off-by: Corey Minyard <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/char/ipmi/ipmi_poweroff.c

···
 	}
 
 	if (atca_oem_poweroff_hook)
-		return atca_oem_poweroff_hook(user);
+		atca_oem_poweroff_hook(user);
  out:
 	return;
 }