gpu: host1x: Refactor channel allocation code

This is largely a rewrite of the Host1x channel allocation code, bringing
several changes:

- The previous code could deadlock due to an interaction
  between the 'reflock' mutex and CDMA timeout handling.
  This gets rid of the mutex.
- Support for more than 32 channels, required for Tegra186
- General refactoring, including better encapsulation
  of channel ownership handling into channel.c

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/host1x/dev.h

@@ -129,10 +129,8 @@ struct host1x {
 	struct host1x_syncpt *nop_sp;
 
 	struct mutex syncpt_mutex;
-	struct mutex chlist_mutex;
-	struct host1x_channel chlist;
-	unsigned long allocated_channels;
-	unsigned int num_allocated_channels;
+
+	struct host1x_channel_list channel_list;
 
 	struct dentry *debugfs;