usb: hold lock throughout resample handler
usb: hold lock throughout resample handler

Rather than acquiring the lock twice, lock it once and hold it while
doing the check and potential follow-up call to interrupt().  This looks
like it could be a race to me, but I don't know if it can actually cause
problems in practice.  In any case, it's better to only acquire the lock
once.

BUG=chromium:831850
TEST=Test adb in Crostini

Change-Id: Id7aa76e543cd5b858faf128f516e8d63e27cf3e7
Signed-off-by: Daniel Verkamp <72bc170b46ec491f7bdd4359a1c0bfed274de40c@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1592579
Commit-Ready: ChromeOS CL Exonerator Bot <fa429e5907f00867f797423aea74327bb02c91b6@appspot.gserviceaccount.com>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Zach Reizner <3374927928a53d04457674c546bd4de57c2044ec@chromium.org>

google/crosvm,google/crosvm,google/crosvm,google/crosvm