Don't set antenna mask for devices that don't support it

Newer iwlwifi parts don't support this antenna mask, and
attempting to set it causes test to fail when the command
errors out complaining about this.  Work around this by
not setting the antenna mask if that operation is not supported.

BUG=chromium:377044
TEST=iwlwifi based parts can set up APs in the 2.4Ghz range after
this patch.

Change-Id: Ife691640c8961d7c19d8a1688718fecd4abe9e04
Reviewed-on: https://chromium-review.googlesource.com/203960
Reviewed-by: Peter Qiu <zqiu@chromium.org>
Reviewed-by: Christopher Wiley <wiley@chromium.org>
Tested-by: Christopher Wiley <wiley@chromium.org>
Commit-Queue: Christopher Wiley <wiley@chromium.org>
3 files changed