tmf: Fix incorrect histogram state when concurrently cleared during drag

tmf: Fix incorrect histogram state when concurrently cleared during drag

- Reset the offset when drag zoom interrupted by clear

- Update selection when drag selection interrupted by clear

- Fix overflow in min and max offset calculation

Change-Id: I6eea70d713d4b46e75d254b9374631623c023600
Signed-off-by: Patrick Tasse <patrick.tasse@gmail.com>
Reviewed-on: https://git.eclipse.org/r/19605
Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
IP-Clean: Bernd Hufmann <bernd.hufmann@ericsson.com>
Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Tested-by: Hudson CI