Kernel: Don't allow userspace to sys$open() literal symlinks

The O_NOFOLLOW_NOERROR is an internal kernel mechanism used for the
implementation of sys$readlink() and sys$lstat().

There is no reason to allow userspace to open symlinks directly.

Kernel/Process.cpp

@@ -1863,6 +1863,9 @@ int Process::sys$open(const Syscall::SC_open_params* user_params)
     auto options = params.options;
     auto mode = params.mode;
 
+    if (options & O_NOFOLLOW_NOERROR)
+        return -EINVAL;
+
     if ((options & O_RDWR) || (options & O_WRONLY))
         REQUIRE_PROMISE(wpath);
     else
@@ -1905,6 +1908,9 @@ int Process::sys$openat(const Syscall::SC_openat_params* user_params)
     int options = params.options;
     u16 mode = params.mode;
 
+    if (options & O_NOFOLLOW_NOERROR)
+        return -EINVAL;
+
     if ((options & O_RDWR) || (options & O_WRONLY))
         REQUIRE_PROMISE(wpath);
     else