Support for digilent Coraz7

[kenkit]

 sudo openFPGALoader -c digilent --detect
empty
Jtag frequency : requested 6.00MHz    -> real 6.00MHz   
index 0:
	idcode   0x4ba00477
	type     ARM cortex A9
	irlength 4
index 1:
	idcode 0x13723093
	manufacturer xilinx
	family zynq
	model  xc7z007s
	irlength 6