drivers: usb: gadget: 64-bit related type fixes

Change-Id: I2f9b12e1e0cdfe64ffe20db78d319a6221821184
Signed-off-by: Greg Hackmann <ghackmann@google.com>
Git-commit: 243a7e84f6527d8c150aacd2c18039219d553a64
Git-repo: https://android.googlesource.com/kernel/common.git


[imaund@codeaurora.org: Correct conflicts related to type fixes and
  an additional change which prevents a length overrun condition.]
Signed-off-by: Ian Maund <imaund@codeaurora.org>