samples: webusb-next: fix USB function buffer alignment

Use proper macro for buffer definition.

Signed-off-by: Johann Fischer <[email protected]>

Author: jfischer-no

samples/subsys/usb/webusb-next/src/sfunc.c

@@ -19,7 +19,7 @@ LOG_MODULE_REGISTER(sfunc, LOG_LEVEL_INF);
 NET_BUF_POOL_FIXED_DEFINE(sfunc_pool,
 			  1, 0, sizeof(struct udc_buf_info), NULL);
 
-static uint8_t __aligned(sizeof(void *)) sfunc_buf[512];
+UDC_STATIC_BUF_DEFINE(sfunc_buf, 512);
 
 struct sfunc_desc {
 	struct usb_if_descriptor if0;