Updates InputDevice.cpp to read input configs from an APEX.

Devices that include these files in an APEX must ensure it is named
as expected by this file: com.android.input.config.

Bug: 197881714
Test: Tested with an input config apex for cuttlefish
Change-Id: Iccccc9bb57e25013aadec6aa0de8e58cbd5c9e68
1 file changed