tools/xenpm: fix FreeBSD build

ENODATA is not defined on FreeBSD:

xenpm.c:1380:17: error: use of undeclared identifier 'ENODATA'
 1380 |         errno = ENODATA;
      |                 ^
1 error generated.

Fixes: edb657887a ("xenpm: Add get-core-temp subcommand")
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Teddy Astie <teddy.astie@vates.tech>
Acked-by: Anthony PERARD <anthony.perard@vates.tech>

tools/misc/xenpm.c

@@ -1377,7 +1377,7 @@ static int fetch_dts_temp(xc_interface *xch, uint32_t cpu, bool package, int *te
     {
     case 0:
         /* This CPU isn't online or can't query this MSR */
-        errno = ENODATA;
+        errno = ENODEV;
         return -1;
 
     case 1: