m68knommu: fix sparse warnings in signal code

Commit 858b810bf63f ("m68knommu: switch to using asm-generic/uaccess.h")
cleaned up a number of sparse warnings associated with lack of __user
annotations. It also uncovered a couple of more in the signal handling
code:

arch/m68k/kernel/signal.c:923:16: expected char [noderef] __user *__x
arch/m68k/kernel/signal.c:923:16: got void *
arch/m68k/kernel/signal.c:1007:16: warning: incorrect type in initializer (different address spaces)
arch/m68k/kernel/signal.c:1007:16: expected char [noderef] __user *__x
arch/m68k/kernel/signal.c:1007:16: got void *
arch/m68k/kernel/signal.c:1132:6: warning: symbol 'do_notify_resume' was not declared. Should it be static?

These are specific to a non-MMU configuration. Fix these inserting the
correct __user annotations as required.

Reported-by: kernel test robot <[e-mail]>
Signed-off-by: Greg Ungerer <[e-mail]>

arch/m68k/kernel/signal.c

···
 	err |= __put_user(0x70004e40 + (__NR_sigreturn << 16),
 			  (long __user *)(frame->retcode));
 #else
-	err |= __put_user((void *) ret_from_user_signal, &frame->pretcode);
+	err |= __put_user((long) ret_from_user_signal,
+			  (long __user *) &frame->pretcode);
 #endif
 
 	if (err)
···
 	err |= __put_user(0x4e40, (short __user *)(frame->retcode + 4));
 #endif
 #else
-	err |= __put_user((void *) ret_from_user_rt_signal, &frame->pretcode);
+	err |= __put_user((long) ret_from_user_rt_signal,
+			  (long __user *) &frame->pretcode);
 #endif /* CONFIG_MMU */
 
 	if (err)