gpu: nvgpu: Replace use of bitops.h and kernel.h

Remove use of linux/kernel.h and linux/compiler.h. We don't use
anything in those headers.

Also replace use of linux/bitops.h with new wrapper nvgpu/bitops.h.

JIRA NVGPU-13

Change-Id: Iefa6b4598d5a5e7fc386c0a7a554e778a87010d6
Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: http://git-master/r/1460777
Reviewed-by: Alex Waterman <alexw@nvidia.com>
Reviewed-by: svccoveritychecker <svccoveritychecker@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Deepak Nibade <dnibade@nvidia.com>

include/linux/tegra_vgpu.h

@@ -19,6 +19,8 @@
 #ifndef __TEGRA_VGPU_H
 #define __TEGRA_VGPU_H
 
+#include <nvgpu/types.h>
+
 enum {
 	TEGRA_VGPU_MODULE_GPU = 0,
 };