DPK is short for digital pre-distortion calibration. It can adjusts digital
waveform according to PA linear characteristics dynamically to enhance
TX EVM.

Do this calibration when we are going to run on AP channel. To prevent
power offset out of boundary, it monitors thermal and set proper boundary
to register.

8852c needs two backup buffers, so we enlarge the array. But, 8852a still
needs only one, so it only uses first element (index zero).
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220502235408.15052-9-pkshih@realtek.com