usb: gadget: function: f_sourcesink: fix sparse warning

this patch fixes following sparse warnings:

f_sourcesink.c:347:34: warning: symbol 'ss_int_source_comp_desc' was not declared. Should it be static?
f_sourcesink.c:365:34: warning: symbol 'ss_int_sink_comp_desc' was not declared. Should it be static?
Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/function/f_sourcesink.c

@@ -344,7 +344,7 @@ static struct usb_endpoint_descriptor ss_int_source_desc = {
 	.bInterval =		USB_MS_TO_SS_INTERVAL(GZERO_INT_INTERVAL),
 };
 
-struct usb_ss_ep_comp_descriptor ss_int_source_comp_desc = {
+static struct usb_ss_ep_comp_descriptor ss_int_source_comp_desc = {
 	.bLength =		USB_DT_SS_EP_COMP_SIZE,
 	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
 
@@ -362,7 +362,7 @@ static struct usb_endpoint_descriptor ss_int_sink_desc = {
 	.bInterval =		USB_MS_TO_SS_INTERVAL(GZERO_INT_INTERVAL),
 };
 
-struct usb_ss_ep_comp_descriptor ss_int_sink_comp_desc = {
+static struct usb_ss_ep_comp_descriptor ss_int_sink_comp_desc = {
 	.bLength =		USB_DT_SS_EP_COMP_SIZE,
 	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,