u16 Create Channel Spec (u8 channel)
- If 2 GHz band
- Set chanspec to 0x2000
- Otherwise
- Set chanspec to 0x1000
- If N mode enabled AND the band width is 40 MHz AND bit 8 is not set in the locale flags AND mimo_cap_40 is true
- Bitwise OR chanspec with 0x0D00
- Otherwise
- Bitwise OR chanspec with 0x0B00
- Bitwise OR chanspec with the channel
- Return chanspec