[run] Set the number of HT chains.

• Set the tx/rx chains based on the existing MIMO eeprom reads
• Add 3-chain rates

Tested:

• MAC/BBP RT5390 (rev 0x0502), RF RT5370 (MIMO 1T1R), 2g/5g STA
• MAC/BBP RT3593 (rev 0x0402), RF RT3053 (MIMO 3T3R), 2g/5g STA