fix hitag functions (issue #798) (#800)

[proxmark3-svn] / fpga / xst_lf.scr

run -ifn fpga_lf.v -ifmt Verilog -ofn fpga_lf.ngc -ofmt NGC -p xc2s30-5-vq100 -top fpga_lf -opt_mode area -opt_level 2 -resource_sharing yes -fsm_style bram -fsm_encoding compact