several missing cpu_to_le16() in ieee80211softmac_capabilities()

on some codepaths we forgot to convert to little-endian as we do on the
rest of them and as the caller expects from us.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: John W. Linville <linville@tuxdriver.com>