commit c0d31b3c upstream.

The commit '2e4c7553 usb: gadget: f_fs: add aio support' broke the
quirk implemented to align buffer size to maxpacketsize on out endpoint.
As result, functionfs does not work on Intel platforms using dwc3 driver
(i.e. Bay Trail and Merrifield). This patch fixes the issue.

This code is based on a previous Qiuxu's patch.

Fixes: 2e4c7553 (usb: gadget: f_fs: add aio support)
Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
[ luis: backported to 3.16: file rename:
  drivers/usb/gadget/function/f_fs.c -> drivers/usb/gadget/f_fs.c ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>