drm/radeon/dpm: remove local sumo_get_xclk()

Use the new asic callback instead.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/sumo_smc.c b/drivers/gpu/drm/radeon/sumo_smc.c
index 22c8151..18abba5 100644
--- a/drivers/gpu/drm/radeon/sumo_smc.c
+++ b/drivers/gpu/drm/radeon/sumo_smc.c
@@ -146,7 +146,7 @@
 {
 	struct sumo_power_info *pi = sumo_get_pi(rdev);
 	u32 period, unit, timer_value;
-	u32 xclk = sumo_get_xclk(rdev);
+	u32 xclk = radeon_get_xclk(rdev);
 
 	unit = (RREG32_RCU(RCU_LCLK_SCALING_CNTL) & LCLK_SCALING_TIMER_PRESCALER_MASK)
 		>> LCLK_SCALING_TIMER_PRESCALER_SHIFT;