usb: don't check pm qos NO_POWER_OFF flag in usb_port_suspend()

usb: don't check pm qos NO_POWER_OFF flag in usb_port_suspend()

The pm qos NO_POWER_OFF flag is checked twice during usb device suspend
to see if the usb port power off condition is met. This is redundant and
also will prevent the port from being powered off if the NO_POWER_OFF
flag is changed to 1 from 0 after the device was already suspended.

More detail in the following link.
	http://marc.info/?l=linux-usb&m=136543949130865&w=2

This patch should be backported to kernels as old as 3.7, that
contain the commit f7ac7787ad361e31a7972e2854ed8dc2eedfac3b "usb/acpi:
Use ACPI methods to power off ports."

Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org