cnss2: Add support XO Clock selection leakage prevention

QCA6490 needs XO clock selection assert for 2ms to latch the clock
configuration before WLAN enable gpio assert. Update cnss platform
driver code to support this gpio toggling.

Change-Id: I31c48365e6b5cfbbeae849f1a9a9ee1dc44050cd
Signed-off-by: Manikandan Mohan <manikand@codeaurora.org>