dt-bindings: arm: fsl: Add Apalis iMX8QP

dt-bindings: arm: fsl: Add Apalis iMX8QP

Add binding documentation for the Apalis iMX8QP SoM mated with Apalis
Ixora and Apalis Evaluation board.

Apalis iMX8QP is a variant of the Apalis iMX8QM, using an NXP i.MX8QP
SoC instead of the i.MX8QM. The two SoCs are pin to pin compatible, with
the i.MX8QP being a lower end variant, with a slower GPU and one Cortex
A72 core instead of two.

The two Apalis SoMs variants share the same schematics and PCB, and the
iMX8QP variant exists only on revision V1.1 of board.

Link: https://www.nxp.com/products/i.MX8
Link: https://www.toradex.com/computer-on-modules/apalis-arm-family/nxp-imx-8
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>