drm/amd/pm: correct the reference clock for fan speed(rpm) calculation

Correct the reference clock as 25Mhz for SMU13 fan speed calculation.
Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0.c

@@ -1261,7 +1261,8 @@ int smu_v13_0_set_fan_speed_rpm(struct smu_context *smu,
 				uint32_t speed)
 {
 	struct amdgpu_device *adev = smu->adev;
-	uint32_t tach_period, crystal_clock_freq;
+	uint32_t crystal_clock_freq = 2500;
+	uint32_t tach_period;
 	int ret;
 
 	if (!speed)
@@ -1271,7 +1272,6 @@ int smu_v13_0_set_fan_speed_rpm(struct smu_context *smu,
 	if (ret)
 		return ret;
 
-	crystal_clock_freq = amdgpu_asic_get_xclk(adev);
 	tach_period = 60 * crystal_clock_freq * 10000 / (8 * speed);
 	WREG32_SOC15(THM, 0, regCG_TACH_CTRL,
 		     REG_SET_FIELD(RREG32_SOC15(THM, 0, regCG_TACH_CTRL),