package/libv4l: bump version to 1.20.0

- removed 0002-keytable-use-input_event-properly.patch
  (upstream [1])

- removed 0003-keytable-add-compatibility-for-input_event_sec.patch
  (upstream [2])

[1] https://git.linuxtv.org/v4l-utils.git/patch/?id=38f4ce74275ae4625463f7eec78764715a0b6246
[2] https://git.linuxtv.org/v4l-utils.git/patch/?id=8b7e6ce9367fe09ca9398b5f3cc75bba2598b162



Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>