Drop redundant header imports with dts/upstream already providing
updated headers which have been checked to be backwards compatibility.

The imx headers which aren't present in dts/upstream are as follows:

- include/dt-bindings/clock/imxrt1020-clock.h
- include/dt-bindings/clock/imx8qm-clock.h
- include/dt-bindings/clock/imxrt1170-clock.h
- include/dt-bindings/clock/imx8qxp-clock.h
- include/dt-bindings/memory/imxrt-sdram.h
- include/dt-bindings/pinctrl/pads-imx8qxp.h
- include/dt-bindings/pinctrl/pads-imx8qm.h
- include/dt-bindings/soc/imx8_pd.h
- include/dt-bindings/soc/imx_rsrc.h

hence these aren't dropped yet but there was an unused header:

- include/dt-bindings/pinctrl/pins-imx8mq.h

which has been dropped as well. There shouldn't be any funtional impact
with this change but it rather allows iMX platforms to use upstream
dt-bindings headers in a backwards compatible manner.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Michael Trimarchi <michael@amarulasolutions.com>

Sync kernel dts for i.MX6UL from
commit <0a8ad0ffa4d8> ("Merge tag 'for-linus-5.3-ofs1' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux")

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>

Add i.MX6UL dtsi support from Linux.

Here is the last commit:
"ARM: dts: add gpio-ranges property to iMX GPIO controllers"
(sha1: bb728d662bed0fe91b152550e640cb3f6caa972c)

Cc: Stefano Babic <sbabic@denx.de>
Cc: Matteo Lisi <matteo.lisi@engicam.com>
Cc: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>

Add i.mx6ul clock header, copied from kernel commit (29b4817d401).
i.MX6ULL reuse the file in Linux Kernel, so let's keep the same.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Stefano Babic <sbabic@denx.de>