rtlwifi: add efuse ops for other components

The new component phydm need to access efuse content, so we prepare ops
for reference.

Signed-off-by: Tsang-Shian Lin <thlin@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>