arch-x86: Hook up the newfstatat system call for 64 bit Linux.

Jira Issue: https://gem5.atlassian.net/browse/GEM5-1117

Change-Id: I711fc7d7009621bb317981293725416ae74d1d3d
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/53206
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>

src/arch/x86/linux/syscall_tbl64.cc

@@ -309,7 +309,7 @@ SyscallDescTable<EmuLinux::SyscallABI64> EmuLinux::syscallDescs64 = {
     { 259, "mknodat", mknodatFunc<X86Linux64> },
     { 260, "fchownat", fchownatFunc<X86Linux64> },
     { 261, "futimesat", futimesatFunc<X86Linux64> },
-    { 262, "newfstatat" },
+    { 262, "newfstatat", newfstatatFunc<X86Linux64> },
     { 263, "unlinkat", unlinkatFunc<X86Linux64> },
     { 264, "renameat", renameatFunc<X86Linux64> },
     { 265, "linkat" },