icnss: Provide API to check the firmware ready status

API check the wlan firmware ready status in icnss platform
data and return the status(true/false) to caller.

CRs-Fixed: 1106520
Change-Id: I1246e6c213011d73ade5078c07bb2190135e54ec
Signed-off-by: Sarada Prasanna Garnayak <sgarna@codeaurora.org>