ARM: dts: imx6sll: e60k02: fix usbotg1 pinctrl

usb@2184000: 'pinctrl-0' is a dependency of 'pinctrl-names'

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Fixes: c100ea86 ("ARM: dts: add Netronix E60K02 board common file")
Signed-off-by: Shawn Guo <shawnguo@kernel.org>