LP PHY TX Power Update Npt

1. Read shared memory location 0xE0 and save in (u16) s3
2. Subtract the private variable lpphy_tssi_tx_cnt from s3 and save in (u16) tx_cnt

3. Read PHY Register 0x4A5, bitwise AND with 0x700, right shift by 8, and save in (u16) npt

4. Left shift 1 by (npt ANDed with 0x1f)
5. If the quantity calculated in the previous step is less then tx_cnt
   1. Store s3 in the private variable lpphy_tss_tx_cnt

   2. If npt < 7

      1. Increment npt

      2. MaskSet PHY Register 0x4A5 with mask 0xF8FF and set with (npt << 8)

   3. Store npt in the private variable lpphy_tssi_npt

   4. Read PHY Register 0x4AB, bitwise AND with 0x7F00, right shift the result by 8, and store the result in the private variable lpphy_tssi_idx