sfc: use sysfs_emit() to instead of scnprintf()

Follow the advice of the Documentation/filesystems/sysfs.rst and show()
should only use sysfs_emit() or sysfs_emit_at() when formatting the
value to be returned to user space.
Signed-off-by: Nye xingchen <ye.xingchen@zte.com.cn>
Reviewed-by: NLeon Romanovsky <leonro@nvidia.com>
Acked-by: NMartin Habets <habetsm.xilinx@gmail.com>
Link: https://lore.kernel.org/r/202212051021451139126@zte.com.cnSigned-off-by: NJakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/sfc/efx_common.c

@@ -1164,7 +1164,7 @@ static ssize_t mcdi_logging_show(struct device *dev,
 	struct efx_nic *efx = dev_get_drvdata(dev);
 	struct efx_mcdi_iface *mcdi = efx_mcdi(efx);
 
-	return scnprintf(buf, PAGE_SIZE, "%d\n", mcdi->logging_enabled);
+	return sysfs_emit(buf, "%d\n", mcdi->logging_enabled);
 }
 
 static ssize_t mcdi_logging_store(struct device *dev,

drivers/net/ethernet/sfc/siena/efx_common.c

@@ -1178,7 +1178,7 @@ static ssize_t mcdi_logging_show(struct device *dev,
 	struct efx_nic *efx = dev_get_drvdata(dev);
 	struct efx_mcdi_iface *mcdi = efx_mcdi(efx);
 
-	return scnprintf(buf, PAGE_SIZE, "%d\n", mcdi->logging_enabled);
+	return sysfs_emit(buf, "%d\n", mcdi->logging_enabled);
 }
 
 static ssize_t mcdi_logging_store(struct device *dev,