msm_11ad: increment reference count on msm_11ad driver

msm_11ad manage the wil6210 node in the device tree.
Increment reference count on msm_11ad driver to prevent
accidental module removal by modprobe.


Change-Id: Ib72908ef4b9cc2237edd265d77fe805e67f12f60
Signed-off-by: Alexei Avshalom Lazar <ailizaro@codeaurora.org>