drm/amd/display: initialize p_state to proper value

[why]
On some modes SMU will be in infinite loop state at boot, this is
because driver assumes p_state_support is false, but this is the
opposite of the assumed boot state by SMU.  we optimize away
notifying SMU about no pstate, and so they will get stuck

[how]
when we init clk manager, init pstate to true, so it matches driver load
assumption

Signed-off-by: Jun Lei <Jun.Lei@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>