gpu: nvgpu: Move channel IOCTL code to Linux module

Move channel IOCTL specific code to Linux module. This clears some
Linux dependencies from channel_gk20a.c.

JIRA NVGPU-32

Change-Id: I41817d612b959709365bcabff9c8a15f2bfe4c60
Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: http://git-master/r/1330804
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

drivers/gpu/nvgpu/common/linux/ioctl_channel.h

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2017, 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.
+ */
+#ifndef __NVGPU_IOCTL_CHANNEL_H__
+#define __NVGPU_IOCTL_CHANNEL_H__
+
+int gk20a_channel_open(struct inode *inode, struct file *filp);
+int gk20a_channel_release(struct inode *inode, struct file *filp);
+long gk20a_channel_ioctl(struct file *filp,
+	unsigned int cmd, unsigned long arg);
+
+#endif