The Xilinx ZynqMP SoC embeds both Cortex-R "RPU" and Cortex-A "APU"
cores.
Since the current Zephyr architecture cannot support AMP of Cortex-R
and Cortex-A within the same project, the RPU and APU should be
considered separate platforms and handled accordingly.
This commit re-purposes the SOC_XILINX_ZYNQMP symbol as a helper symbol
indicating that Xilinx ZynqMP SoC is used, and adds a new symbol,
SOC_XILINX_ZYNQMP_RPU, for specifying the actual build target platform.
When Cortex-A support is added in the future, SOC_XILINX_ZYNQMP_APU
symbol should be added and used to conditionally handle APU-specific
code.
For more details, refer to the issue #20217.
Signed-off-by: Stephanos Ioannidis <root@stephanos.io>