media: rc: ite-cir: fix min_timeout calculation

Commit 528222d8 ("media: rc: harmonize infrared durations to
microseconds") missed to switch the min_timeout calculation from ns
to us. This resulted in a minimum timeout of 1.2 seconds instead of 1.2ms,
leading to large delays and long key repeats.

Fix this by applying proper ns->us conversion.

Cc: stable@vger.kernel.org
Fixes: 528222d8 ("media: rc: harmonize infrared durations to microseconds")
Signed-off-by: Matthias Reichl <hias@horus.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>