readelf: fix sframe memory leak

Not a significant leak, but there is no need for this strdup.

	* readelf (parse_args): Don't strdup ".sframe" passed to
	request_dump_byname.
diff --git a/binutils/readelf.c b/binutils/readelf.c
index c98569a..b594034 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -6991,8 +6991,7 @@
 	  else
 	    {
 	      do_dump = true;
-	      const char *sframe_sec_name = strdup (".sframe");
-	      request_dump_byname (sframe_sec_name, SFRAME_DUMP);
+	      request_dump_byname (".sframe", SFRAME_DUMP);
 	    }
 	  break;
 	case OPTION_DYN_SYMS: