This patch fixes a bug in checking for HT40 mode.
The STA's mode can be determined from the cached HT capabilities,
use that and remove the redundant variable 'rc_phy_mode'.
Signed-off-by: Sujith <Sujith.Manoharan@atheros.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>