drm/amd/display: fix odm k2 div calculation

Correct setting is div by 2 for odm. Seamless odm transitions
are enabled with enable_dp_dig_pixel_rate_div_policy debug flag.

Fixes: a2c7356f ("drm/amd/display: fix pixel rate update sequence")
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Dmytro Laktyushkin <dmytro.laktyushkin@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>