MLK-11853 ARM: dts: imx6qp-sabreauto: remove the enet pin reconfig

MLK-11853 ARM: dts: imx6qp-sabreauto: remove the enet pin reconfig

Tuning MMDC ZQ_PU_OFFSET impact DDR IO timing like the value is greater
than 0x9 causing enet lost packets due to the worse timing. Reinforce
ENET DDR IO drive strength can fix the issue. Use the default pin setting
can match the RGMII timing for AI board.

Worse timing cause performance drop, the performance has no drop after
enhancing the DDR IO pins drive strength. Pass over night test.

Signed-off-by: Fugang Duan <B38611@freescale.com>
(cherry picked from commit: 5ceb746c0358c0851187a3f4f6f61d02e951eae0)

Conflicts:
	arch/arm/boot/dts/imx6qp-sabreauto.dts