wifi: rtw89: return failure if needed firmware elements are not recognized

WiFi 7 chips doesn't have static const tables defined in driver. If tables
aren't loaded properly from firmware file, driver can get NULL pointer
access exception. One way is to add the checking statements when trying to
access these tables, but I choose to check them right after loading
firmware elements from firmware file, so I don't need to add error handlers
everywhere.

Currently, the needed firmware elements of WiFi 6 chips are all zero, and
coming WiFi 7 chip will need at least BB MCU, parameters of BB and RF.
We will add them after 8922AE is verified.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230801021127.15919-9-pkshih@realtek.com