ARM: dts: imx6: Disable "weim" node in the dtsi files

Commit 1be81ea5 ("ARM: dts: imx6: Add imx-weim parameters to
dtsi's") causes the following probe error when the weim node is not
present on the board dts (such as imx6q-sabresd):

imx-weim 21b8000.weim: Invalid 'ranges' configuration
imx-weim: probe of 21b8000.weim failed with error -22

There is no need to always enable the "weim" node on mx6. Do the same
as in the other i.MX dtsi files where "weim" is disabled and only gets
enabled on a per dts basis.

All the imx6 weim dts users explicitily provide 'status = "okay"', so
this change has no impact on current imx6 weim users.

If a board does not use the weim driver it will not describe its 'ranges'
property, so simply disable the 'weim' node in the imx6 dtsi files to
avoid such probe error message.

Fixes: 1be81ea5 ("ARM: dts: imx6: Add imx-weim parameters to dtsi's")
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>