usb: otg: don't set a_alt_hnp_support feature for OTG 2.0 device

Since a_alt_hnp_support is obsolete in OTG 2.0, HNP capable host should
send this set feature request only if the otg device is connecting to a
non-HNP port and it's compliant with OTG 1.x revision. This is done by
checking its otg descriptor length, OTG 2.0 uses usb_otg20_descriptor
which has different length than OTG 1.x using usb_otg_descriptor.

Signed-off-by: Li Jun <jun.li@freescale.com>
Acked-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>