MAINTAINERS: update clkdev location

Commit 6d803ba7 ("ARM: 6483/1: arm & sh: factorised duplicated
clkdev.c") moved it to a separate directory.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>