gpu: nvgpu: post dbg session event from os specific code

As part of debug session unification following changes are
required.

-Including bug.h header file to fix the compilation issue
on QNX

- The mechanism of posting debug events is OS specific. In Linux
this works through poll fd, wherein we can make use of nvgpu_cond
variables to poll and trigger the corresponding wait_queue
via nvgpu_cond_broadcast_interruptible() call.

The post event functionality on QNX doesn't work on poll though.
It uses iofunc_notify_trigger to post the debug events to calling
process. As such QNX can't work with nvgpu_cond's.

To overcome this issue, it is proposed to create a OS specific
interface for posting debugger events. Linux can call
nvgpu_cond_broadcast_interruptible() in its implementation, which
makes sense since these are already initialized and poll'ed in the
Linux specific code only.
QNX can implement this interface to call iofunc_notify_* functions,
as per its need

Jira VQRM-2363

Change-Id: I0abdc0787f771040b8aff5384290d7e6549f81fb
Signed-off-by: Sourab Gupta <sourabg@nvidia.com>
Signed-off-by: Prateek Sethi <prsethi@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1696368
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-by: Richard Zhao <rizhao@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

drivers/gpu/nvgpu/common/linux/ioctl_dbg.c

@@ -468,6 +468,11 @@ free_ref:
 	return err;
 }
 
+void nvgpu_dbg_session_post_event(struct dbg_session_gk20a *dbg_s)
+{
+	nvgpu_cond_broadcast_interruptible(&dbg_s->dbg_events.wait_queue);
+}
+
 static int dbg_unbind_single_channel_gk20a(struct dbg_session_gk20a *dbg_s,
 			struct dbg_session_channel_data *ch_data)
 {