The SCMI binding clearly states the value of #thermal-sensor-cells must
be 1. However arch/arm64/boot/dts/freescale/imx8ulp.dtsi sets it 0 which
results in the following warning with dtbs_check:

  |  arch/arm64/boot/dts/freescale/imx8ulp-evk.dt.yaml: scmi:
  | 		protocol@15:#thermal-sensor-cells:0:0: 1 was expected
  |	From schema: Documentation/devicetree/bindings/firmware/arm,scmi.yaml

Fix it by setting it to 1 as required.

Cc:Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Acked-by: Peng Fan <peng.fan@nxp.com>
Fixes: a38771d7 ("arm64: dts: imx8ulp: add scmi firmware node")
Signed-off-by: Shawn Guo <shawnguo@kernel.org>