linux-user: Ignore broken loop ioctl

During invocations of losetup, we run into an ioctl that doesn't
exist. However, because of that we output an error, which then
screws up the kiwi logic around that call.

So let's silently ignore that bogus ioctl.

Signed-off-by: Alexander Graf <agraf@suse.de>
[AF: Rebased for v2.1.0-rc0]
Signed-off-by: Andreas Färber <afaerber@suse.de>

linux-user/syscall.c

@@ -3821,6 +3821,13 @@ static abi_long do_ioctl_kdsigaccept(const IOCTLEntry *ie, uint8_t *buf_temp,
     return get_errno(ioctl(fd, ie->host_cmd, sig));
 }
 
+static abi_long do_ioctl_fail(const IOCTLEntry *ie, uint8_t *buf_temp, int fd,
+                              abi_long cmd, abi_long arg)
+{
+    /* Fail silently */
+    return -EINVAL;
+}
+
 static IOCTLEntry ioctl_entries[] = {
 #define IOCTL(cmd, access, ...) \
     { TARGET_ ## cmd, cmd, #cmd, access, 0, {  __VA_ARGS__ } },