MAINTAINERS: update ADP5520 pattern

Typo in path.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>