drm/amd/display: add guard for SMU ver, for 48mhz clk

[why]
dp_48m_refclk_driver_pwdn is persistent through S3 and S5.
This was worked arround in SMU FW 55.21.0. Earlier FW don't have this fix
so we will hang on reboot

[how]
add a guard for smu versions before SMU FW 55.21.0
Signed-off-by: Joseph Gravenor <joseph.gravenor@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c

@@ -649,7 +649,7 @@ void rn_clk_mgr_construct(
 			pp_smu->rn_funcs.set_wm_ranges(&pp_smu->rn_funcs.pp_smu, &ranges);
 	}
 
-	if (!IS_FPGA_MAXIMUS_DC(ctx->dce_environment)) {
+	if (!IS_FPGA_MAXIMUS_DC(ctx->dce_environment) && clk_mgr->smu_ver >= 0x00371500) {
 		/* enable powerfeatures when displaycount goes to 0 */
 		rn_vbios_smu_enable_48mhz_tmdp_refclk_pwrdwn(clk_mgr, !debug->disable_48mhz_pwrdwn);
 	}