staging: speakup: add spaces around minus

Add spaces around minus operator. Reported by checkpatch.
Signed-off-by: Ioannis Valasakis <code@wizofe.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/speakup/speakup_acntpc.c

@@ -298,7 +298,7 @@ static void accent_release(void)
 {
 	spk_stop_serial_interrupt();
 	if (speakup_info.port_tts)
-		synth_release_region(speakup_info.port_tts-1, SYNTH_IO_EXTENT);
+		synth_release_region(speakup_info.port_tts - 1, SYNTH_IO_EXTENT);
 	speakup_info.port_tts = 0;
 }