Use dedicated lock in InputController

Sharing the single lock with VirtualDeviceImpl doesn't make sense
since they don't really share resources which cannot be accessed
concurrently.

The shared lock lead to deadlock described in b/270703290, using
dedicated lock in InputController removes resource allocation cycle
which caused that deadlock instance.

Bug: 270703290
Test: atest VirtualMouseTest --iterations 20
Test: atest CtsHardwareTestCases
Test: atest CtsVirtualDevicesTestCases
Test: atest VirtualDeviceManagerServiceTest
Change-Id: Id12a945e182a5516ee06193a4fa475b863f11846