arm64: dts: xilinx: add soc-specific spi compatibles for zynqmp/versal-net

arm64: dts: xilinx: add soc-specific spi compatibles for zynqmp/versal-net

Unlike zynq, which has a specific compatible for the Cadence spi
controller, zynqmp and versal-net do not have specific compatibles.
In order to "encourage" people to use soc-specific compatibles for new
devices using this IP, add specific compatibles for these devices, with
a fallback to the existing compatible for the r1p6 version of the IP so
that there will be no functional change.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/20251001-cheesy-shucking-c55431bbcae3@spud
Signed-off-by: Michal Simek <michal.simek@amd.com>