MAINTAINERS: change my DT related maintainer address

MAINTAINERS: change my DT related maintainer address

Filtering capabilities on my work email are pretty much non-existent and this
has turned out to be something of a firehose...

Cc: Stephen Warren <[email protected]>
Cc: Rob Herring <[email protected]>
Cc: Olof Johansson <[email protected]>
Cc: Linus Walleij <[email protected]>
Signed-off-by: Ian Campbell <[email protected]>
Acked-by: Pawel Moll <[email protected]>
Acked-by: Mark Rutland <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>