Do not shuffle scno inside syscall_name

This makes interface a bit irregular otherwise.

* defs.h (syscall_name): Clarify description.
* syscall.c (syscall_name): Do not call shuffle_scno.
* printsiginfo.c (print_si_info) <case SIGSYS>: Use shuffle_scno.

defs.h

@@ -400,7 +400,7 @@ extern int get_scno(struct tcb *);
 extern kernel_ulong_t get_rt_sigframe_addr(struct tcb *);
 
 /**
- * Convert syscall number to syscall name.
+ * Convert a (shuffled) syscall number to the corresponding syscall name.
  *
  * @param scno Syscall number.
  * @return     String literal corresponding to the syscall number in case latter

printsiginfo.c

@@ -209,8 +209,8 @@ print_si_info(const siginfo_t *sip)
 			 *  - Looks like there are no other cases where SIGSYS
 			 *    is delivered from the kernel so far.
 			 */
-			const char *scname =
-				syscall_name((unsigned) sip->si_syscall);
+			const char *scname = syscall_name(shuffle_scno(
+				(unsigned) sip->si_syscall));
 
 			tprints(", si_call_addr=");
 			printaddr(ptr_to_kulong(sip->si_call_addr));

syscall.c

@@ -1276,7 +1276,5 @@ get_syscall_result(struct tcb *tcp)
 const char *
 syscall_name(kernel_ulong_t scno)
 {
-	scno = shuffle_scno(scno);
-
 	return scno_is_valid(scno) ? sysent[scno].sys_name : NULL;
 }