r8169: add handling DASH when DASH is disabled

For devices that support DASH, even DASH is disabled, there may still
exist a default firmware that will influence device behavior.
So driver needs to handle DASH for devices that support DASH, no
matter the DASH status is.

This patch also prepares for "fix network lost after resume on DASH
systems".

Fixes: ee7a1beb

 ("r8169:call "rtl8168_driver_start" "rtl8168_driver_stop" only when hardware dash function is enabled")
Cc: stable@vger.kernel.org
Signed-off-by: ChunHao Lin <hau@realtek.com>
Reviewed-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/20231109173400.4573-2-hau@realtek.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>