libxc: adjust string size calculations in xc_{,de,test_}assign_dt_device()

In preparation for a hypervisor change also include the nul terminator in
the size calculations.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Teddy Astie <teddy.astie@vates.tech>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Anthony PERARD <anthony.perard@vates.tech>

tools/libs/ctrl/xc_domain.c

@@ -1592,7 +1592,7 @@ int xc_assign_dt_device(
     char *path)
 {
     int rc;
-    size_t size = strlen(path);
+    size_t size = strlen(path) + 1;
     struct xen_domctl domctl = {};
     DECLARE_HYPERCALL_BOUNCE(path, size, XC_HYPERCALL_BUFFER_BOUNCE_IN);
 
@@ -1624,7 +1624,7 @@ int xc_test_assign_dt_device(
     char *path)
 {
     int rc;
-    size_t size = strlen(path);
+    size_t size = strlen(path) + 1;
     struct xen_domctl domctl = {};
     DECLARE_HYPERCALL_BOUNCE(path, size, XC_HYPERCALL_BUFFER_BOUNCE_IN);
 
@@ -1652,7 +1652,7 @@ int xc_deassign_dt_device(
     char *path)
 {
     int rc;
-    size_t size = strlen(path);
+    size_t size = strlen(path) + 1;
     struct xen_domctl domctl = {};
     DECLARE_HYPERCALL_BOUNCE(path, size, XC_HYPERCALL_BUFFER_BOUNCE_IN);