drm/amd/display: Fix VPG instancing for dcn314 HPO

[Why]
An issue during VPG indexing offset generation causing
to use the incorrect VPG. HW team placed VPG instances
5 at end of list, making it VPG 9 in register headers.

[How]
Correct VPG instance for HPO encoders.

Reviewed-by: Charlene Liu <Charlene.Liu@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Duncan Ma <duncan.ma@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>