drm/amd/display: Remove redundant 'else' statement in dcn1_update_clocks

[Why]
DM has impelemented new pp_smu interface. 'Else' is not longer needed.

Signed-off-by: Fatemeh Darbehani <fatemeh.darbehani@amd.com>
Reviewed-by: Eric Yang <eric.yang2@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Acked-by: Yongqiang Sun <yongqiang.sun@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>