soundwire: cadence: simplify with cleanup.h

Allocate the memory with scoped/cleanup.h to reduce error handling and
make the code a bit simpler.

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/soundwire/cadence_master.c

···
  * Used by Master driver
  */
 
+#include <linux/cleanup.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/debugfs.h>
···
 static int cdns_reg_show(struct seq_file *s, void *data)
 {
 	struct sdw_cdns *cdns = s->private;
-	char *buf;
 	ssize_t ret;
 	int num_ports;
 	int i, j;
 
-	buf = kzalloc(RD_BUF, GFP_KERNEL);
+	char *buf __free(kfree) = kzalloc(RD_BUF, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
 
···
 		ret += cdns_sprintf(cdns, buf, ret, CDNS_PDI_CONFIG(i));
 
 	seq_printf(s, "%s", buf);
-	kfree(buf);
 
 	return 0;
 }