cfg80211: fix beacon interval in interface combination iteration

cfg80211: fix beacon interval in interface combination iteration

We shouldn't abort the iteration with an error when one of the
potential combinations can't accomodate the beacon interval
request, we should just skip that particular combination. Fix
the code to do so.

CRs-Fixed: 1087922
Change-Id: Ib1ae7221291b8176d61d58e756a3814c80d98d27
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git
Git-commit: 0507a3ac6e98f50583912ec78d07c2e4daaf2b28
[liord@codeaurora.org: cherry-pick without changes]
Signed-off-by: Lior David <liord@codeaurora.org>