Fix no video output when boot up system with type-c port

[koba]

[Impact]
Connect a WD19SC/WD19TB/typeC2hdmi converter on the machine type-c port, video can't output to the external monitor.

[Fix]
The patch is provided by Imre(https://patchwork<email address hidden>).

Correct the typo during output setup.
Fix a typo that led to some MST short pulse event handling issue (the
short pulse event was handled for both encoder instances, each having
its own state).

[Test Case]
1. Connected the WD19SC/WD19TB/typeC2hdmi converter with the TGL platform's Type-C port and
connected the external monitor on WD19SC/WD19TB/type-c2hdmi with HDMI/Displayport.
2. Cold boot the TGL platform.
3. Check the monitor can be blinked and the video can output to the monitor.

[Where problems could occur]
Just correct the typo and have low regression risk.

[koba (kobako)]

verified on 5.10-oem-1013

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux-oem-5.10 - 5.10.0-1013.14

---------------
linux-oem-5.10 (5.10.0-1013.14) focal; urgency=medium

  * focal/linux-oem-5.10: 5.10.0-1013.14 -proposed tracker (LP: #1914024)

  * Fix no video output when boot up system with type-c port (LP: #1914020)
    - drm/i915/tgl: Fix typo during output setup

 -- Timo Aaltonen <email address hidden> Mon, 01 Feb 2021 12:47:03 +0200