Ignore v4l2 select() return when stopping capture

With some slightly broken webcams, it's possible that the select()
returns with a timeout or no event. In that case, the v4l2 thread
never returns. To fix this, just check if quit_ is set and exit
unconditionally in that case.

https://bugzilla.mozilla.org/show_bug.cgi?id=1752326

Bug: None
Change-Id: Ic07ce15afd0016ff9f967c2cf64e646c20127457
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/251540
Reviewed-by: Magnus Flodman <mflodman@webrtc.org>
Reviewed-by: Per Kjellander <perkj@webrtc.org>
Commit-Queue: Per Kjellander <perkj@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#36200}
diff --git a/AUTHORS b/AUTHORS
index e4729a5..212c990 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -80,6 +80,7 @@
 Min Wang <mingewang@gmail.com>
 Mo Zanaty <mzanaty@cisco.com>
 Niek van der Maas <mail@niekvandermaas.nl>
+Olivier Crête <olivier.crete@ocrete.ca>
 Pali Rohar
 Paul Kapustin <pkapustin@gmail.com>
 Peng Yu <yupeng323@gmail.com>