sparc: kill ancient comment in sparc_sigaction()

It used to be true, until 2.1.78 (14 years ago) when we switched to
do_sigaction()...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/sparc/kernel/sys_sparc_32.c

@@ -195,11 +195,6 @@ sparc_sigaction (int sig, const struct old_sigaction __user *act,
 	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 
 	if (!ret && oact) {
-		/* In the clone() case we could copy half consistent
-		 * state to the user, however this could sleep and
-		 * deadlock us if we held the signal lock on SMP.  So for
-		 * now I take the easy way out and do no locking.
-		 */
 		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
 		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
 		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||