ARM: dts: at91: sam9x60: Define pinctrl node with its label

ARM: dts: at91: sam9x60: Define pinctrl node with its label

Define the pinctrl nodes with its label to align with the Linux DT.
Without this change the pinmux nodes are grouped under an additional
'pinctrl' child node which is not identified by the pinctrl driver
when the GPIO banks are made as child nodes of pinctrl node.

Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
Signed-off-by: Manikandan Muralidharan <manikandan.m@microchip.com>
Reviewed-by: Eugen Hristev <eugen.hristev@linaro.org>