cnss: dynamic power control when do suspend/resume

In current wlan suspend/resume design, wlan chip only enter suspend/wow
mode but keep wlan chip power always on when device goes to suspend
state.
This design provide a method to control wlan chip power off/on when
device goes to suspend/resume state. Introduce gChangeSleepPowerMode
tunable in INI file to user for this power control:
- 0, do not make wlan chip power off/on when device goes to
     suspend/resume state.
- 1, only turn off/on WLAN_EN but keep WLAN_VDD power on when device
     goes to suspend/resume.
- 2, turn off/on both WLAN_VDD and WLAN_EN when device goes to
     suspend/resume.

CRs-fixed: 2414283
Change-Id: I17d80d4b894cab4cd4a4eadfc00c4213aed1f911
Signed-off-by: Ke Huang <keh@codeaurora.org>