drm/amd/display: Add i2c speed arbitration for dc_i2c and hdcp_i2c

[why]
HDCP 1.4 failed on SL8800 SW w/a test driver use.

[how]
Slow down the HW i2c speed when used by HW i2c.
This request: each acquired_i2c_engine setup the i2c speed needed
and sets the I2c engine for HDCP use at release_engine.

This covers SW using HW i2c engine and HDCP using HW i2c engine.
for dmcu using HW i2c engine, needs add similar logic in dmcu fw.

Signed-off-by: Charlene Liu <Charlene.Liu@amd.com>
Reviewed-by: Chris Park <Chris.Park@amd.com>
Acked-by: Eryk Brol <eryk.brol@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>