drm/amd/pm: Fix clock reporting for SMUv13.0.6

On SMU v13.0.6, effective clocks are reported by FW which won't exactly
match with DPM level. Report the current clock based on the values
matching closest to the effective clock. Also, when deep sleep is
applied to a clock, report it with a special level "S:" as in sample
clock levels below

S: 19Mhz *
0: 615Mhz
1: 800Mhz
2: 888Mhz
3: 1000Mhz

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>