UPSTREAM: Input: allow drivers specify timestamp for input events

Currently, evdev stamps events with timestamps acquired in evdev_events()
However, this timestamping may not be accurate in terms of measuring
when the actual event happened.

Let's allow individual drivers specify timestamp in order to provide a more
accurate sense of time for the event. It is expected that drivers will set the
timestamp in their hard interrupt routine.

Bug: 150896413
Signed-off-by: Atif Niyaz <atifniyaz@google.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Change-Id: I718209b41958a771c48f6069a597cec469c4074d
(cherry picked from commit 3b51c44bd6936e86a7180abd9aebc4387a479253)
Signed-off-by: Hridya Valsaraju <hridya@google.com>