tools: hv: include string.h in hv_fcopy_daemon

The usage of strchr requires inclusion of string.h.

Fixes: 0c38cda6 ("tools: hv: remove unnecessary header files and netlink related code")
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

tools/hv/hv_fcopy_daemon.c

@@ -21,6 +21,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <string.h>
 #include <errno.h>
 #include <linux/hyperv.h>
 #include <linux/limits.h>