init: allow properties to be used for the keycodes option

Bug: 117828597
Test: bugreport launches with a test property set to appropriate keys
Test: bugreport doesn't launch with the test property unset
Test: no errors seen in build or boot in either of the above cases
Change-Id: Iea27032080a0a7863932b1c1b573857ac66b56b5
2 files changed