powerpc/papr_scm: use dev_get_drvdata

Eliminate direct accesses to the driver_data field.
Signed-off-by: Haowen Bai <baihaowen@meizu.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1653988790-19999-1-git-send-email-baihaowen@meizu.com

arch/powerpc/platforms/pseries/papr_scm.c

@@ -354,7 +354,7 @@ static int papr_scm_pmu_get_value(struct perf_event *event, struct device *dev,
 {
 	struct papr_scm_perf_stat *stat;
 	struct papr_scm_perf_stats *stats;
-	struct papr_scm_priv *p = (struct papr_scm_priv *)dev->driver_data;
+	struct papr_scm_priv *p = dev_get_drvdata(dev);
 	int rc, size;
 
 	/* Allocate request buffer enough to hold single performance stat */