rtl8187: Fix more frag bit checking, rts duration calc

rtl8187: Fix more frag bit checking, rts duration calc

patch 98798f4875b7149db4eb7d0a126fc6dcd9637821 in mainline.

The wrong pointer is passed to ieee80211_get_morefrag. Fix this.

While we're at it, reorder things so they look better and the rts duration
calculation is done with the right length.

Thanks to Christoph Hellwig for finding the ieee80211_get_morefrag issue.

Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>