Add IPA-related nodes and definitions to "sdx65.dtsi".  The SMP2P
nodes (ipa_smp2p_out and ipa_smp2p_in) are already present.

Enable IPA in "sdx65-mtp.dts"; this GSI firmware is loaded by Trust
Zone on this platform.
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Tested-by: Rohit Agarwal <quic_rohiagar@quicinc.com>
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230327195605.2854123-2-elder@linaro.org