Implement the basic serial driver first, and then we can talk about
"custom" configurations and the like, using the correct apis.
Without the SI4455_IOC_SEZC call, the driver can't configure the Si4455 and not working at all.
The cofiguration for interface is provided by user for application.
It contains the base frequency, channel spacing, modulation, and a lot of more stuff, and generated by Silicon Labs Wireless Development Suite.
The generated configuration is in a non public(compressed, encrypted...who knows) format, so without this the driver can't provide configuration parameters to Si4455.