MAINTAINERS: add scripts/dtc under Devicetree maintainers

scripts/dtc has no explicit in kernel maintainer, so add it under
Devicetree maintainers.

Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>

MAINTAINERS

@@ -5035,6 +5035,7 @@ S:	Maintained
 F:	Documentation/devicetree
 F:	drivers/of
 F:	include/linux/of*.h
+F:	scripts/dtc
 K:	of_get_property
 K:	of_match_table