arm64: dts: qcom: sdm630: assign adsp_mem region to ADSP FastRPC node

arm64: dts: qcom: sdm630: assign adsp_mem region to ADSP FastRPC node

Downstream [1] ADSP FastRPC node has the adsp_mem region assigned, so
assign it to the ADSP FastRPC node.

[1]: https://github.com/xiaomi-sdm660/android_kernel_xiaomi_sdm660/blob/11-EAS/arch/arm/boot/dts/qcom/sdm660.dtsi#L1693

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Ekansh Gupta <ekansh.gupta@oss.qualcomm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Nickolay Goppen <setotau@mainlining.org>
Link: https://lore.kernel.org/r/20260429-qcom-sdm660-cdsp-adsp-fastrpc-dts-fix-v5-5-16bc82e622ad@mainlining.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>