staging: brcm80211: remove phy_version.h

Removed the file phy_version.h from the driver sources. It was not
used. For keeping track of the phy version, which is a separately
developed component, one definition has been kept and placed in
wlc_phy_int.h.

Signed-off-by: Arend van Spriel <arend@broadcom.com>
Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>