ibex: change compensation type to INTERNAL
ibex: change compensation type to INTERNAL

INTERNAL compensation type is the only one supported in nextpnr-xilinx

Signed-off-by: Wojciech Tatarski <431121b10bd310643d219c632c934b4c1f5d4931@antmicro.com>

SymbiFlow/fpga-tool-perf,SymbiFlow/fpga-tool-perf,SymbiFlow/fpga-tool-perf,SymbiFlow/fpga-tool-perf