ptp_ocp: use device_find_any_child() instead of custom approach

We have already a helper to get the first child device, use it and
drop custom approach.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Vadim Fedorenko <vadfed@fb.com>
Link: https://lore.kernel.org/r/20220921141005.2443-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/ptp/ptp_ocp.c

@@ -1311,12 +1311,6 @@ ptp_ocp_read_eeprom(struct ptp_ocp *bp)
 	goto out;
 }
 
-static int
-ptp_ocp_firstchild(struct device *dev, void *data)
-{
-	return 1;
-}
-
 static struct device *
 ptp_ocp_find_flash(struct ptp_ocp *bp)
 {
@@ -1325,7 +1319,7 @@ ptp_ocp_find_flash(struct ptp_ocp *bp)
 	last = NULL;
 	dev = &bp->spi_flash->dev;
 
-	while ((dev = device_find_child(dev, NULL, ptp_ocp_firstchild))) {
+	while ((dev = device_find_any_child(dev))) {
 		if (!strcmp("mtd", dev_bus_name(dev)))
 			break;
 		put_device(last);