ARM: dts: imx6qdl-sabrelite: remove erratum ERR006687 workaround

There is a pin conflict with GPIO_6. This pin functions as a power
input pin to the OV5642 camera sensor, but ENET uses it as the h/w
workaround for erratum ERR006687, to wake-up the ARM cores on normal
RX and TX packet done events. So we need to remove the h/w workaround
to support the OV5642. The result is that the CPUidle driver will no
longer allow entering the deep idle states on the sabrelite.

This is a partial revert of

commit 6261c4c8 ("ARM: dts: imx6qdl-sabrelite: use GPIO_6 for FEC
			interrupt.")
commit a28eeb43 ("ARM: dts: imx6: tag boards that have the HW workaround
			for ERR006687")

Signed-off-by: Steve Longerbeam <steve_longerbeam@mentor.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>