arm64: dts: xilinx: Apply overlays to base dtbs

arm64: dts: xilinx: Apply overlays to base dtbs

DT overlays in tree need to be applied to a base DTB to validate they
apply, to run schema checks on them, and to catch any errors at compile
time. Defining the "-dtbs" variable is not enough as the combined DT must
be added to dtbs-y.

zynqmp-sck-kr-g-revA.dtso and zynqmp-sck-kr-g-revB.dtso don't exist, so drop
them.

Signed-off-by: Rob Herring <robh@kernel.org>
Fixes: 45fe0dc4ea2e ("arm64: xilinx: Use zynqmp prefix for SOM dt overlays")
Link: https://lore.kernel.org/r/20230911214751.2202913-1-robh@kernel.org
Signed-off-by: Michal Simek <michal.simek@amd.com>