ia64: Fix typo in unwinder which could cause NULL-pointer dereferences.

arch/ia64/kernel/unwind.c

@@ -1746,7 +1746,7 @@ run_script (struct unw_script *script, struct unw_frame_info *state)
 			if (!state->pri_unat_loc)
 				state->pri_unat_loc = &state->sw->ar_unat;
 			/* register off. is a multiple of 8, so the least 3 bits (type) are 0 */
-			s[dst+1] = (*state->pri_unat_loc - s[dst]) | UNW_NAT_MEMSTK;
+			s[dst+1] = ((unsigned long) state->pri_unat_loc - s[dst]) | UNW_NAT_MEMSTK;
 			break;
 
 		      case UNW_INSN_SETNAT_TYPE: