MAINTAINERS: add drm and drm/i915 bug filing info

Link: http://lkml.kernel.org/r/1476966135-26943-2-git-send-email-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS

@@ -4026,6 +4026,7 @@ DRM DRIVERS
 M:	David Airlie <airlied@linux.ie>
 L:	dri-devel@lists.freedesktop.org
 T:	git git://people.freedesktop.org/~airlied/linux
+B:	https://bugs.freedesktop.org/
 S:	Maintained
 F:	drivers/gpu/drm/
 F:	drivers/gpu/vga/
@@ -4078,6 +4079,7 @@ M:	Jani Nikula <jani.nikula@linux.intel.com>
 L:	intel-gfx@lists.freedesktop.org
 L:	dri-devel@lists.freedesktop.org
 W:	https://01.org/linuxgraphics/
+B:	https://01.org/linuxgraphics/documentation/how-report-bugs
 Q:	http://patchwork.freedesktop.org/project/intel-gfx/
 T:	git git://anongit.freedesktop.org/drm-intel
 S:	Supported