SystemUI: fix up navigation cursor keyevent flags

Volume cursor controls use slightly different flags to keep the cursor
within the field. Match them in the SystemUI for consistent (and better)
behavior.

Change-Id: I56d597f111ec611b0ca24a10f30575401fa76d18
Signed-off-by: Roman Birg <roman@cyngn.com>
Merge "SystemUI: fix up navigation cursor keyevent flags" into pac-4.4