ARM: dts: imx: Add dr_mode host setting to all host-only usb instances

The chipidea driver adds an extra line of spam to the log when a
host-only chipidea instance is left set to the default of a dual role
controller.

[    2.010873] ci_hdrc ci_hdrc.1: doesn't support gadget

Set the dr_mode property to host on all the host-only nodes
to avoid this warning.

Signed-off-by: Matt Porter <mporter@konsulko.com>
Acked-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>