wil6210: remove reference to preset_chandef

The field preset_chandef of wireless_dev must not be accessed
by the driver because it is private to cfg80211. Store the
monitor channel locally in wil6210_priv instead.

Change-Id: Ie3a5fb48d4e4dcbd731f89c8dcf415a6fb44fae5
Signed-off-by: Lior David <qca_liord@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Git-commit: 7d3e4dbe570e79940624ff46387e34db741dcb5c
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git


Signed-off-by: Maya Erez <merez@codeaurora.org>