usb: gadget: f_uac1: prepare for separate compilation

Integrating configfs requires converting f_uac1 to new function interface,
which in turn requires converting it to the new function interface,
which involves separate compilation of f_uac1.c into usb_f_uac1.ko.
u_uac1.c contains some module parameters. After this patch is applied
they are still a part of the resulting g_audio.ko, but can be guarded
with a compatiblity flag which will be removed when no users of the old
function interface of f_uac1 are left.
Tested-by: Sebastian Reimers <sebastian.reimers@googlemail.com>
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/function/f_uac1.c

@@ -15,6 +15,7 @@
 #include <linux/atomic.h>
 
 #include "u_uac1.h"
+#include "u_uac1.c"
 
 #define OUT_EP_MAX_PACKET_SIZE	200
 static int req_buf_size = OUT_EP_MAX_PACKET_SIZE;

drivers/usb/gadget/legacy/audio.c

@@ -81,7 +81,6 @@ static struct usb_function *f_uac2;
 
 #ifdef CONFIG_GADGET_UAC1
 #include "u_uac1.h"
-#include "u_uac1.c"
 #include "f_uac1.c"
 #endif