rtw88: 8723d: Add basic chip capabilities

RTL8723DE is an 11n 1x1 2.4G single band chip with the
following capabilities:

 - TX/RX BD size: 16/8
 - TX/RX desc size: 40/24
 - physical/logical/protected efuse size: 512/512/96
 - TX gain index factor: 1
 - max TX power index: 0x3F
 - band: 2G
 - HT: support
 - VHT: Not support

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/20200420055054.14592-2-yhchuang@realtek.com