wifi: rtw89: 8851b: add to read efuse version to recognize hardware version B

8851B hardware version A and B use different firmware, but register version
code of these two are the same, so add this helper to read efuse version to
determine which version is installed.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230512061220.16544-2-pkshih@realtek.com