usb: clean up clippy unit_arg warning

Fix the last instance of this clippy warning:

  warning: passing a unit value to a function

... and remove this warning from the "To be resolved" list in
bin/clippy.

BUG=None
TEST=bin/clippy passes without warnings

Change-Id: Ic1d558e935366d80eeadb96bf1ff951ce50edd5b
Signed-off-by: Daniel Verkamp <dverkamp@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/1766623
Reviewed-by: Dylan Reid <dgreid@chromium.org>
Reviewed-by: Tomasz Jeznach <tjeznach@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>

2 files changed, 1 insertions, 2 deletions

diff --git a/bin/clippy b/bin/clippy
index 9f31816..66df660 100755
--- a/bin/clippy
+++ b/bin/clippy
@@ -20,7 +20,6 @@ SUPPRESS=(
     let_unit_value
     question_mark
     range_plus_one
-    unit_arg
 
     # We don't care about these lints. Okay to remain suppressed globally.
     blacklisted_name
diff --git a/devices/src/usb/xhci/xhci_transfer.rs b/devices/src/usb/xhci/xhci_transfer.rs
index 400cbbc..fa6d5de 100644
--- a/devices/src/usb/xhci/xhci_transfer.rs
+++ b/devices/src/usb/xhci/xhci_transfer.rs
@@ -291,7 +291,7 @@ impl XhciTransfer {
                 // If the device is gone, we don't need to send transfer completion event, cause we
                 // are going to destroy everything related to this device anyway.
                 return match self.port.detach() {
-                    Ok(v) => Ok(v),
+                    Ok(()) => Ok(()),
                     // It's acceptable for the port to be already disconnected
                     // as asynchronous transfer completions are processed.
                     Err(HubError::AlreadyDetached(_e)) => Ok(()),