example/KR260: Add example design for KR260

Signed-off-by: Alex Forencich <alex@alexforencich.com>

README.md

@@ -94,6 +94,7 @@ Example designs are provided for several different FPGA boards, showcasing many
 *  Digilent Arty A7 (Xilinx Artix 7 XC7A35T)
 *  Xilinx KC705 (Xilinx Kintex 7 XC7K325T)
 *  Xilinx KCU105 (Xilinx Kintex UltraScale XCKU040)
+*  Xilinx KR260 (Xilinx Kria K26 SoM / Zynq UltraScale+ XCK26)
 *  Xilinx VCU108 (Xilinx Virtex UltraScale XCVU095)
 
 ## Testing