Enable Clippy and fix warnings am: 2b13024f5f am: 02be88aaaa

Original change: https://android-review.googlesource.com/c/trusty/app/keymint/+/3105940

Change-Id: I3a4739342f88bdf87ce3a66defc2a4433fd2fbc9
Signed-off-by: Automerger Merge Worker <[email protected]>