virtio: uapi: avoid usage of libc types

Using libc types and headers from the UAPI headers is problematic as it
introduces a dependency on a full C toolchain.

On Linux 'unsigned long' works as a replacement for 'uintptr_t' and does
not depend on libc.

Signed-off-by: Thomas Weißschuh <[e-mail]>
Acked-by: Arnd Bergmann <[e-mail]>
Signed-off-by: Michael S. Tsirkin <[e-mail]>
Message-Id: <[e-mail]>

include/uapi/linux/virtio_ring.h

···
  * SUCH DAMAGE.
  *
  * Copyright Rusty Russell IBM Corporation 2007. */
-#ifndef __KERNEL__
-#include <stdint.h>
-#endif
 #include <linux/types.h>
 #include <linux/virtio_types.h>
 
···
 	vr->num = num;
 	vr->desc = p;
 	vr->avail = (struct vring_avail *)((char *)p + num * sizeof(struct vring_desc));
-	vr->used = (void *)(((uintptr_t)&vr->avail->ring[num] + sizeof(__virtio16)
+	vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + sizeof(__virtio16)
 		+ align-1) & ~(align - 1));
 }