Add CONFIG_LLCC68_MAX_PAYLOAD_LENGTH with a default of 128 bytes and a hardware-bounded range of 1..255.
Wire both the C++ and raw C LLCC68 payload buffer constants to the Kconfig value so application builds can tune radio buffer RAM without editing headers.
Rename the fixed-length 100k preset from GMSK to GFSK and expose rx_bandwidth_hz() next to the GfskRxBandwidth enum so applications can report configured bandwidth without carrying driver-specific lookup tables.
crosstyan
ce56757dac