ARM: dts: at91: sam9_l9260: Modify information in LED nodes.

Add power led node and rename status led node.

Signed-off-by: Raashid Muhammed <raashidmuhammed@zilogic.com>
Reviewed-by: Vijay Kumar B. <vijaykumar@bravegnu.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>