hwmon: (pmbus/core) Replace deprecated strncpy() with strscpy()

strncpy() is deprecated for NUL-terminated destination buffers; use
strscpy() instead.

Compile-tested only.

Note(groeck): strscpy() uses sizeof() to determine the length of the
destination buffer if it is not provided as argument.

Link: KSPP#90
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Link: https://lore.kernel.org/r/20250227173936.7746-2-thorsten.blum@linux.dev
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Author: toblux

drivers/hwmon/pmbus/pmbus_core.c

@@ -1470,8 +1470,7 @@ static int pmbus_add_label(struct pmbus_data *data,
 	snprintf(label->name, sizeof(label->name), "%s%d_label", name, seq);
 	if (!index) {
 		if (phase == 0xff)
-			strncpy(label->label, lstring,
-				sizeof(label->label) - 1);
+			strscpy(label->label, lstring);
 		else
 			snprintf(label->label, sizeof(label->label), "%s.%d",
 				 lstring, phase);