drm/amdgpu/pm/smu11: Fix fan set speed bug

Fix fan set speed calculation.

Suggested-by: Kenneth Feng <kenneth.feng@amd.com>
Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Kenneth Feng <kenneth.feng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/swsmu/smu11/smu_v11_0.c

@@ -1187,7 +1187,12 @@ int smu_v11_0_set_fan_speed_rpm(struct smu_context *smu,
 	if (ret)
 		return ret;
 
-	crystal_clock_freq = amdgpu_asic_get_xclk(adev);
+	/*
+	 * crystal_clock_freq div by 4 is required since the fan control
+	 * module refers to 25MHz
+	 */
+
+	crystal_clock_freq = amdgpu_asic_get_xclk(adev) / 4;
 	tach_period = 60 * crystal_clock_freq * 10000 / (8 * speed);
 	WREG32_SOC15(THM, 0, mmCG_TACH_CTRL,
 		     REG_SET_FIELD(RREG32_SOC15(THM, 0, mmCG_TACH_CTRL),