ccid-card-passthru: fix regression in realize()

Since cc847bfd, CCID card-passthru
fails to intialize, because it changed a debug line to an error,
probably by mistake. Change it back to a DPRINTF debug.

(solves Boxes creating VM with smartcard passthru failing to start)
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180515153039.27514-1-marcandre.lureau@redhat.com
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/usb/ccid-card-passthru.c

@@ -345,7 +345,7 @@ static void passthru_realize(CCIDCardState *base, Error **errp)
     card->vscard_in_pos = 0;
     card->vscard_in_hdr = 0;
     if (qemu_chr_fe_backend_connected(&card->cs)) {
-        error_setg(errp, "ccid-card-passthru: initing chardev");
+        DPRINTF(card, D_INFO, "ccid-card-passthru: initing chardev");
         qemu_chr_fe_set_handlers(&card->cs,
             ccid_card_vscard_can_read,
             ccid_card_vscard_read,