arm64: dts: tqma8mpql: Remove invalid/unused property

arm64: dts: tqma8mpql: Remove invalid/unused property

'dr_mode' is part of the USB DWC3 core, not the glue layer. Remove the
property from glue layer. Fixes the dtbs_check warning:
arch/arm64/boot/dts/freescale/imx8mp-tqma8mpql-mba8mpxl.dtb: usb@32f10108:
  'dr_mode' does not match any of the regexes: '^usb@[0-9a-f]+$',
  'pinctrl-[0-9]+'
 from schema $id: http://devicetree.org/schemas/usb/fsl,imx8mp-dwc3.yaml#

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>