rtw88: 8723d: Organize chip TX/RX FIFO

TX FIFO size is 32k and it was divided into 256 pages with 128 bytes.
A boundary is used to split pages into two parts, head part is used to
store TX packets coming from host, and tail part is reserved for special
purposes, such as beacon packet, null data packet and so on.

The TX packets coming from host have many categories, such as VO, VI, BE,
BK, MG and etc. When going into head part of TX FIFO, they are classified
to four priority queue named low, normal, high and extra priority queues.
Each priority queue occupies predefined number of page, if a certain
priority queue is full, TX packet will store into PUB priority queue.

Similarly, RX FIFO is 16k and split into two parts, head part is used to
store RX packets, and tail part is 128 bytes and used to store report.
Thus, we fill this boundary to register as well.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200422034607.28747-8-yhchuang@realtek.com