dt-bindings: ata: qcom,ipq806x-ahci: use dtschema

Remove old text bindings and add ipq806x AHCI compatible to
ahci-common.yaml, as well as its required properties.

Signed-off-by: Rayyan Ansari <rayyan.ansari@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>