gpu: nvgpu: Make sure there an nvlink.h header for POSIX

This header doesn't have anything in it yet but the header is
now present. A change recently went in that only checked for
__KERNEL__ before falling back to including the QNX header.
This caused the POSIX build in GVS to attempt to include the
QNX header. The QNX src is not synced in userspace dev-kernel
tests builds resulting in a missing header.

JIRA NVGPU-525

Change-Id: I60f29ad69cbed38b6ea47f95ca504dab51fa01e7
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1714083
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

drivers/gpu/nvgpu/include/nvgpu/nvlink.h

@@ -27,6 +27,8 @@
 
 #ifdef __KERNEL__
 #include <nvgpu/linux/nvlink.h>
+#elif defined(__NVGPU_POSIX__)
+#include <nvgpu/posix/nvlink.h>
 #else
 #include <nvgpu_rmos/include/nvlink.h>
 #endif

drivers/gpu/nvgpu/include/nvgpu/posix/nvlink.h

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2018, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __NVGPU_POSIX_NVLINK_H__
+#define __NVGPU_POSIX_NVLINK_H__
+
+/*
+ * Empty...
+ */
+
+#endif