dynamic_sensor: Support timing out sensor operations.

Bug: 226012902
Test: Used uhid-sample to add a dynamic sensor and verified it can be
 sampled.
Test: Simulated start sampling ioctl timeout and verified operation
 completes with a timeout and eventually cleans up.
Test: Simulated start sampling ioctl timeout with device removal before
 completion and verified operation completes with a timeout and
 eventually cleans up.
Change-Id: I9a957bc1e4000b2c587278146ecbe6e903010616
2 files changed