hw/arm/xlnx-zcu102: Don't enable PSCI conduit when booting guest in EL3

hw/arm/xlnx-zcu102: Don't enable PSCI conduit when booting guest in EL3

Change the Xilinx ZynqMP-based board xlnx-zcu102 to use the new
boot.c functionality to allow us to enable psci-conduit only if
the guest is being booted in EL1 or EL2, so that if the user runs
guest EL3 firmware code our PSCI emulation doesn't get in its
way.

To do this we stop setting the psci-conduit property on the CPU
objects in the SoC code, and instead set the psci_conduit field in
the arm_boot_info struct to tell the common boot loader code that
we'd like PSCI if the guest is starting at an EL that it makes
sense with.

Note that this means that EL3 guest code will have no way
to power on secondary cores, because we don't model any
kind of power controller that does that on this SoC.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Niek Linnenbank <nieklinnenbank@gmail.com>
Tested-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Tested-by: Cédric Le Goater <clg@kaod.org>
Tested-by: Niek Linnenbank <nieklinnenbank@gmail.com>
Acked-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220127154639.2090164-7-peter.maydell@linaro.org