wifi: rtlwifi: Remove rtl_intf_ops.read_efuse_byte

PCI drivers and USB drivers can both use the same function,
read_efuse_byte(), and they can call it directly.

rtl8192de was the only user.

Tested only with the upcoming rtl8192du driver.

Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/4e2c968d-f25c-4a40-be97-4fdcbdde69cf@gmail.com