wil6210: send uevent when creating sysfs files

Send a KOBJ_CHANGE uevent when creating the wil6210 sysfs directory.
This is mainly needed so selinux policy rules will be applied when
the wil6210 module is dynamically loaded.

Change-Id: I4220c551b8792d419db7a380b16f3c87204be22a
Signed-off-by: Lior David <liord@codeaurora.org>