Add getKeyCharacteristics method to KeyMint

(cherry picked from commit 402d62f7bee0ef162d25543886a5310b1ebb9221)

Bug: 186685601
Test: Treehugger
Merged-In: Ie72d865a37e2b6834fe6a86bf843d30286384aa5
Change-Id: Ie72d865a37e2b6834fe6a86bf843d30286384aa5
2 files changed