This patch adds a check for concurrent interfaces while calling
interface up. This avoids to have different mac parameters on one phy.
Otherwise it could be that a interface can overwrite current phy mac
settings which is set by an another interface.
Signed-off-by: NAlexander Aring <alex.aring@gmail.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>