wcnss: configure iris into cxo mode

configure iris into cxo mode when iris card not present
to avoid crash at boot time.

Change-Id: I7056ca9269be05598ffdc5545ee5647a6e432046
CRs-fixed: 691946
Signed-off-by: Hardik Kantilal Patel <hkpatel@codeaurora.org>