cnss: Control vdd-wlan-xtal-aon-supply regulator in cnss platform driver

vdd-wlan-xtal-aon-supply(LD0-4) need to be voted by cnss platform
driver to keep wlan XO(LDO-5) ON during APPS suspend on mdmcalifornium
platforms when wlan is turned ON as per Power UP sequence. Currently
LDO-4 is only voted by USB driver when USB is connected. On removing USB,
LDO-4 is turned off resulting LDO-5 turned off.

When WLAN is turned on removing LDO-5 vote resulted in beaconing failures
on mdmcalifornium platforms. Hence add a dummy vote to LDO-4 when WLAN is
turned ON.

Change-Id: I0c6e7a6c2dc6a51fb19a9d31ceb6823fe9a05ae2
CRs-Fixed: 996537
Signed-off-by: Komal Seelam <kseelam@codeaurora.org>