dt-bindings: mfd: qcom,tcsr: Drop simple-mfd from IPQ6018

Commit 7677ed11 ("dt-bindings: mfd: qcom,tcsr: Convert to dtschema")
converted bindings to DT schema literally - including the
qcom,tcsr-ipq6018 expecting syscon and simple-mfd.  Such configuration
is not used in DTS and there is no actual need of it.  The TCSR block is
purely configuration block and should not have children.  Any child
device should be simply moved outside of TCSR syscon block.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20220909091056.128949-1-krzysztof.kozlowski@linaro.org