[WCNCR00147391] power-save: support PM module for SDIO

[Description]
Add SDIO suspend/resume functions for Linux PM module.
(No WoW support)

Suspend flow:
System suspend trigger
    => call link down in cfg80211_suspend()
    => wait for FW own back in mtk_sdio_pm_suspend()
    => Driver suspend done

* SDIO driver sends ownership back to FW in idle state automatically.
* FW would run for power-save mode by itself. What driver needs
to do is waiting for FW own back.
* Driver has to ask Kernel keeping SDIO bus power-on.
(sdio_set_host_pm_flags)

For SDIO low-power suspend, please check efuse as well.
SH commnet efuse settings:
0x25=0x02
0x32=0x20
0x33=0xA0
0x38=0x03

Feature: power-save
Change-Id: I5988afbb7a2438e200312cafda0e627fa75ea81f
Signed-off-by: Deren Wu <deren.wu@mediatek.com>
CR-Id: WCNCR00147391
1 file changed