ARM: dts: imx6qdl-dhcom: Add USB overcurrent pin on SoM layer

Add USB overcurrent pin muxing on SoM layer. On DRC02 and PDK2 the USB
overcurrent pin isn't connected, but a USB hub on the board takes care
of the USB overcurrent instead. Therefore disable it there with the
property disable-over-current.

Signed-off-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Marek Vasut <marex@denx.de>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: kernel@dh-electronics.com
To: linux-arm-kernel@lists.infradead.org
Reviewed-by: Marek Vasut <marex@denx.de>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>