ALSA: lx646es: Fix possible uninitialized variable reference

lx_pipe_state() checks the return value from lx_message_send_atomic()
and breaks the loop only when it's a negative value.  However,
lx_message_send_atomic() may return a positive error code (as the
return code from the hardware), and then lx_pipe_state() tries to
compare the uninitialized current_state variable.

Fix this behavior by checking the positive non-zero error code as
well.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>