nvgpu: gk20a: include proper header file

Fixed the following sparse warning by including the "fb_gk20a.h" header file:
- fb_gk20a.c: warning: symbol 'fb_gk20a_reset' was not declared.
	      Should it be static?

Bug 200088648

Change-Id: I1ba6051455a22e81da6598eebdccfa8b45b78c3e
Signed-off-by: Amit Sharma (SW-TEGRA) <amisharma@nvidia.com>
Reviewed-on: http://git-master/r/768203
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Sachin Nikam <snikam@nvidia.com>
Reviewed-on: http://git-master/r/770654

drivers/gpu/nvgpu/gk20a/fb_gk20a.c

@@ -1,7 +1,7 @@
 /*
  * GK20A memory interface
  *
- * Copyright (c) 2014, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2014-2015, 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,
@@ -19,6 +19,7 @@
 #include "kind_gk20a.h"
 #include "hw_mc_gk20a.h"
 #include "hw_fb_gk20a.h"
+#include "fb_gk20a.h"
 
 void fb_gk20a_reset(struct gk20a *g)
 {