qcacld-3.0: Define macro WLAN_SYSFS for feature sysfs interface

Disable this feature for MOBILE_ROUTER product, since some MOBILE_ROUTER
platform will attach two wlan cards with separate wlan driver,
during second driver loading process, it will report a warning of
"cannot create duplicate filename" as node with same name has been
created after first driver was loaded.

Change-Id: I9e06439b3a6dacdf4eb5ae87898338ab1eeb8b16
CRs-Fixed: 2295391