icnss: Remove sending uevent after FW ready

FW ready indication doesn't mean it is safe to access HW register.
FW ready only means that WLAN FW is initialized. The HW register
is safe to access only after FW ack the wlan enable mode request.
Hence removing uevent in FW ready indication handler. WLAN driver
will responsible for setting FW ready state once wlan enable mode
request is return success.

CRs-Fixed: 2168628
Change-Id: I769d848efb9dd427da0d71494090fcbf9514cfb2
Signed-off-by: Yuanyuan Liu <yuanliu@codeaurora.org>