maintainers: add bugs and chat URLs for amdgpu

Add links to the issue tracker and the IRC channel for the amdgpu
driver.

Signed-off-by: Simon Ser <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: Christian König <[email protected]>
Cc: Pan Xinhui <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

Author: emersion

MAINTAINERS

@@ -15296,6 +15296,8 @@ M:	Pan, Xinhui <[email protected]>
 L:	[email protected]
 S:	Supported
 T:	git https://gitlab.freedesktop.org/agd5f/linux.git
+B:	https://gitlab.freedesktop.org/drm/amd/-/issues
+C:	irc://irc.oftc.net/radeon
 F:	drivers/gpu/drm/amd/
 F:	drivers/gpu/drm/radeon/
 F:	include/uapi/drm/amdgpu_drm.h