add a new function to set the AGC since the code is a bit different for RT3572. fix the initial AGC value for >=RT3070 while i'm here.
add a new function to set the AGC since the code is a bit different
for RT3572. fix the initial AGC value for >=RT3070 while i'm here.

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars