Adjust BB LOFT Cancel

The table offset used below is passed in from the caller

Retrieve the saved copy of PHYRegister 0x6B
Take bits 0-7 of the value
Take bits 8-15 of the value and shift right by 8 bits
If bit 7 is set in either value, subtract 0x100 from the value (results in signed 8 bit values)
Multiply the Table value requested with each of the signed 8 bit values and then add 0x20, then shift the result right by 6
Clamp both results between -15 and 15
If either value is less than than zero now, add 0x100 to the value and mask with 0xFF
Shift the value that came from bits 8-15 left by 8
Bitwise OR the two values together and write the result to PHYRegister 0x6A