kvm tools: 9p: fix compilation broken by new stat structures

Commit 447c50943fd0 ("9p: Modify the stat structures to use kuid_t and
kgid_t") broke the 9p backend by introducing the k{u,g}id_t types, which
aren't currently in scope.

Just fix the damn thing by including linux/uidgid.h.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

virtio/9p-pdu.c

@@ -5,6 +5,7 @@
 #include <stdint.h>
 
 #include <linux/compiler.h>
+#include <linux/uidgid.h>
 #include <net/9p/9p.h>
 
 static void virtio_p9_pdu_read(struct p9_pdu *pdu, void *data, size_t size)

virtio/9p.c

@@ -18,6 +18,7 @@
 
 #include <linux/virtio_ring.h>
 #include <linux/virtio_9p.h>
+#include <linux/uidgid.h>
 #include <net/9p/9p.h>
 
 static LIST_HEAD(devs);