wifi: rtl8xxxu: Dump the efuse only for untested devices

It appears this was the intention all along, but commit 3307d840
("rtl8xxxu: Add initial code to parse rtl8192eu efuse") initialised
rtl8xxxu_debug with RTL8XXXU_DEBUG_EFUSE for no apparent reason, which
made it dump the efuse for all devices, even the tested ones.

Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>
Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/d53fcf97-d6d2-3c75-14d5-97b58a5f3a6c@gmail.com