Add some missing 'static's.

Change-Id: Id76bb1e954e8fa36a11a38b5445c87f4a64af799
diff --git a/adb/usb_linux_client.cpp b/adb/usb_linux_client.cpp
index f337ccd..1d6ed94 100644
--- a/adb/usb_linux_client.cpp
+++ b/adb/usb_linux_client.cpp
@@ -82,7 +82,7 @@
     struct func_desc fs_descs, hs_descs;
 } __attribute__((packed));
 
-struct func_desc fs_descriptors = {
+static struct func_desc fs_descriptors = {
     .intf = {
         .bLength = sizeof(fs_descriptors.intf),
         .bDescriptorType = USB_DT_INTERFACE,
@@ -109,7 +109,7 @@
     },
 };
 
-struct func_desc hs_descriptors = {
+static struct func_desc hs_descriptors = {
     .intf = {
         .bLength = sizeof(hs_descriptors.intf),
         .bDescriptorType = USB_DT_INTERFACE,