N PHY TX Power Recalc Target

1. If 802.11 Core Revision is 11 or 12
   1. Set bit 0x80 in MAC control
   2. Do dummy read of MAC control
   3. Delay 1 usec

2. Call N PHY TX Power Control Enable with nphy_txpwrctrl as argument

3. If 802.11 Core Revision is 11 or 12
   1. Clear bit 0x80 in MAC control