MAINTAINERS: GDB: update e-mail address

This entry was created with my personal e-mail address.  Update this entry
to my open-source kernel.org account.

Link: http://lkml.kernel.org/r/20180806143904.4716-4-kieran.bingham@ideasonboard.com
Signed-off-by: Kieran Bingham <kbingham@kernel.org>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS

@@ -5930,7 +5930,7 @@ F:	Documentation/dev-tools/gcov.rst
 
 GDB KERNEL DEBUGGING HELPER SCRIPTS
 M:	Jan Kiszka <jan.kiszka@siemens.com>
-M:	Kieran Bingham <kieran@bingham.xyz>
+M:	Kieran Bingham <kbingham@kernel.org>
 S:	Supported
 F:	scripts/gdb/