hw/usb/dev-hid: Support side and extra mouse buttons for usb-tablet

The necessary plumbing for side- and extra mouse buttons to reach
usb-tablet is already done. But the descriptor advertises three buttons
max. Increase this to 5. Buttons are now identical to usb-mouse.

Signed-off-by: Thomas Lambertz <patch@thomaslambertz.de>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
diff --git a/hw/usb/dev-hid.c b/hw/usb/dev-hid.c
index 54d064e..96623aa 100644
--- a/hw/usb/dev-hid.c
+++ b/hw/usb/dev-hid.c
@@ -491,14 +491,14 @@
     0xa1, 0x00,		/*   Collection (Physical) */
     0x05, 0x09,		/*     Usage Page (Button) */
     0x19, 0x01,		/*     Usage Minimum (1) */
-    0x29, 0x03,		/*     Usage Maximum (3) */
+    0x29, 0x05,		/*     Usage Maximum (5) */
     0x15, 0x00,		/*     Logical Minimum (0) */
     0x25, 0x01,		/*     Logical Maximum (1) */
-    0x95, 0x03,		/*     Report Count (3) */
+    0x95, 0x05,		/*     Report Count (5) */
     0x75, 0x01,		/*     Report Size (1) */
     0x81, 0x02,		/*     Input (Data, Variable, Absolute) */
     0x95, 0x01,		/*     Report Count (1) */
-    0x75, 0x05,		/*     Report Size (5) */
+    0x75, 0x03,		/*     Report Size (3) */
     0x81, 0x01,		/*     Input (Constant) */
     0x05, 0x01,		/*     Usage Page (Generic Desktop) */
     0x09, 0x30,		/*     Usage (X) */