BACKPORT: mwifiex: do not declare wdev as pointer

wdev is used even after del_virtual_interface handler in cfg80211
in nl80211_post_doit. Since we have freed wdev in handling of
del_virtual_intf, this can result into crash while deleting
interface.
Avoid this be not declaring wdev which part of
mwifiex_private structure but struct wireless_dev type.

Signed-off-by: Avinash Patil <patila@marvell.com>
Signed-off-by: Cathy Luo <cluo@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
(cherry picked from commit 4facc34a1f1d6ba8fafc9afdb84f9c6ed4334c4c)

BUG=chrome-os-partner:47848
TEST=Compile kernel for oak.

Change-Id: I79785bb6287bf3204ac6997d864f76bacb18b94b
Reviewed-on: https://chromium-review.googlesource.com/314670
Commit-Ready: Wei-Ning Huang <wnhuang@chromium.org>
Tested-by: Wei-Ning Huang <wnhuang@chromium.org>
Reviewed-by: Wei-Ning Huang <wnhuang@chromium.org>
10 files changed