Set max trigger word length for FELIX controller
To run a scan in FW mode, FELIX needs 32x16bit commands. YARR by default writes 32x32bit commands in the trigger loop, which cannot easily be truncated within the FELIX controller to the needed size. To resolve this, a new variable was introduced to the Rd53b and ItkPixV2 trigger loops to set the maximum trigger word length. The default value is 32, but the FELIX controller sets its own value as 16.