drm/amd/display: Enable P-state validation checks for DCN314

[Why]
To align with DCN31 behavior. This helps avoid p-state hangs in
the case where underflow does occur.

[How]
Flip the bit to true.

Reviewed-by: Hansen Dsouza <hansen.dsouza@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>