drm/amd/display: Set memclk levels to be at least 1 for dcn32

[Why]
Cannot report 0 memclk levels even when SMU does not provide any.

[How]
When memclk levels reported by SMU is 0, set levels to 1.

Tested-by: Mark Broadworth <mark.broadworth@amd.com>
Reviewed-by: Martin Leung <Martin.Leung@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Dillon Varone <Dillon.Varone@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>