drm/amd/display: Remove a redundant check in authenticated_dp

[WHY]
mod_hdcp_execute_and_set returns (*status == MOD_HDCP_STATUS_SUCCESS).
When it return 0, it is guaranteed that status == MOD_HDCP_STATUS_SUCCESS
will be evaluated as false. Since now we are using goto out already, all 3
if (status == MOD_HDCP_STATUS_SUCCESS) clauses are guaranteed to enter.
Therefore we are removing the if statements due to redundancy.

Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>