drm/amd/display: DP link layer test 4.2.1.1 fix due to specs update

drm/amd/display: DP link layer test 4.2.1.1 fix due to specs update

[why]
DP link layer CTS specs updated to change the test parameters in test
4.2.1.1.
Before it requires source to delay 400us on aux no reply.
With the specs updates Errata5, it requires source to delay 3.2ms
(based on LTTPR aux timeout)
This causes our test to fail after updating with the latest test
equipment firmware.

[how]
the change is to allow LTTPR 3.2ms aux timeout delay by default.
And only set to 400us if LTTPR is not present.
Before this piece of logic is interwined with LTTPR support.
Now we will default to 3.2ms aux timeout even if LTTPR support is not
enabled by driver.

Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>