Add a module parameter to select deep PS mode. And the mode
cannot be changed after the module has been inserted and probed.
If anyone wants to change the deep mode, should change the mode
and probe the device again to setup the changed deep mode.

When the device is probed, driver will check the deep PS mode
with different IC's PS mode suppotability. If none of the
PS mode is matched, the deep PS mode is changed to NONE,
means deep PS is disabled.
Signed-off-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>