simple_lmk: Print a message when the timeout is reached

This aids in selecting an adequate timeout. If the timeout is hit often
and Simple LMK is killing too much, then the timeout should be
lengthened. If the timeout is rarely hit and Simple LMK is not killing
fast enough under pressure, then the timeout should be shortened.

Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: Danny Lin <danny@kdrag0n.dev>