brcm80211: smac: remove obsolete srom variables from n-phy

The n-phy requested some srom variables that are no longer needed
and consequently not present in the srom revision 8 and higher that
this driver support. This code has been removed from the n-phy.

Reviewed-by: Alwin Beukers <alwin@broadcom.com>
Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>