rtlwifi: Add spec_ver to check whether use new rate-id or not

The field spec_ver is IC's specification mask for common code to do proper
process to specified IC. This commit add a field new rate ID for new
generation IC.

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>