cnss2: Support runtime power on/off WLAN device

WLAN host driver may do runtime mode switch which requires platform
driver to reset device and re-download firmware. Add the changes for
runtime power on/off WLAN device to support runtime mode switch.

Change-Id: I08d3635afbaafb73691fbdf5d25877fb433bae18
CRs-fixed: 2059087
Signed-off-by: Yue Ma <yuem@codeaurora.org>