isxdigit -> qemu_isxdigit

Hi!

Attached patch uses qemu_isxdigit() instead of isxdigit().
Fixes build warning on NetBSD.
Signed-off-by: NChristoph Egger <Christoph.Egger@amd.com>

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Advanced Micro Devices GmbH
Karl-Hammerschmidt-Str. 34, 85609 Dornach b. Muenchen
Geschaeftsfuehrer: Thomas M. McCoy, Giuliano Meroni
Sitz: Dornach, Gemeinde Aschheim, Landkreis Muenchen
Registergericht Muenchen, HRB Nr. 43632

hw/qdev-properties.c

@@ -117,9 +117,9 @@ static int parse_mac(DeviceState *dev, Property *prop, const char *str)
     char *p;
 
     for (i = 0, pos = 0; i < 6; i++, pos += 3) {
-        if (!isxdigit(str[pos]))
+        if (!qemu_isxdigit(str[pos]))
             return -1;
-        if (!isxdigit(str[pos+1]))
+        if (!qemu_isxdigit(str[pos+1]))
             return -1;
         if (i == 5 && str[pos+2] != '\0')
             return -1;