xhci: allow bytewise capability register reads

Some guests need this according to
Alejandro Martinez Ruiz <alex@securiforest.com>

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit 6ee021d)

Conflicts:

	hw/usb/hcd-xhci.c

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

hw/usb/hcd-xhci.c

@@ -2474,8 +2474,10 @@ static void xhci_mem_write(void *ptr, target_phys_addr_t addr,
 static const MemoryRegionOps xhci_mem_ops = {
     .read = xhci_mem_read,
     .write = xhci_mem_write,
-    .valid.min_access_size = 4,
+    .valid.min_access_size = 1,
     .valid.max_access_size = 4,
+    .impl.min_access_size = 4,
+    .impl.max_access_size = 4,
     .endianness = DEVICE_LITTLE_ENDIAN,
 };