arndale: fix unknown status

set status to Maintained
Signed-off-by: NMinkyu Kang <mk7.kang@samsung.com>
Cc: Krzysztof Kozlowski <krzk@kernel.org>

board/samsung/arndale/MAINTAINERS

 ARNDALE BOARD
 M:	Krzysztof Kozlowski <krzk@kernel.org>
-S:	Odd Fixes
+S:	Maintained
 F:	board/samsung/arndale/
 F:	include/configs/arndale.h
 F:	configs/arndale_defconfig