imx-usb-loader: bump version to 4aa9809

Fixes imx-usb-loader usability for i.MX6 QP (failes with the current
version/patch stack).

Changes since e539461:

  9a88413 portable.h: fix build with gcc older than 4.8
  bf25425 add mx6ull_usb_work.conf
  1041959 correct commit "portable.h: fix build with gcc older than 4.8"
  f000130 mx6ull_usb_work.conf: fix copy/paste error in comment
  e99a093 portable: fix typo s/&&/&/ in BE16 fix
  eed0280 portable: use __builtin_bswap16 for BE16 if >= 4.8 GNUC
  95fe112 imx_usb: fix type on imx_usb help
  4aa9809 imx_uart: fix type on help

Remove upstream applied patch ([1]):

 - 0001-portable.h-fix-build-with-gcc-older-than-4.8.patch

[1] https://github.com/boundarydevices/imx_usb_loader/commit/9a88413996c6cfa8b903641f2f52b3fe487595cc



Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>