smack: lsm: remove the unneeded result variable

Return the value smk_ptrace_rule_check() directly instead of storing it
in another redundant variable.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Xu Panda <xu.panda@zte.com.cn>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

security/smack/smack_lsm.c

@@ -496,13 +496,11 @@ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
  */
 static int smack_ptrace_traceme(struct task_struct *ptp)
 {
-	int rc;
 	struct smack_known *skp;
 
 	skp = smk_of_task(smack_cred(current_cred()));
 
-	rc = smk_ptrace_rule_check(ptp, skp, PTRACE_MODE_ATTACH, __func__);
-	return rc;
+	return smk_ptrace_rule_check(ptp, skp, PTRACE_MODE_ATTACH, __func__);
 }
 
 /**