usb-linux: Enlarge buffer for descriptors to 8192 bytes

1024 bytes is way to small, one hd UVC webcam I have over here has so
many resolutions its descriptors take op close to 4k. Hopefully 8k will
be enough for all devices.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

usb-linux.c

@@ -115,7 +115,7 @@ typedef struct USBHostDevice {
     USBDevice dev;
     int       fd;
 
-    uint8_t   descr[1024];
+    uint8_t   descr[8192];
     int       descr_len;
     int       configuration;
     int       ninterfaces;