Staging: r8187se: Fix compile error from wireless-testing commit 7044cc56

In wireless-testing, commit 7044cc56 added struct ieee80211_hdr_3addr
to include/linux/ieee80211.h. This definition collides with one that is
in the r8187se driver in staging.

The conflict is resolved by changing r8187se to use the definition from
include/linuc/ieee80211.h.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>