staging: speakup: avoid out-of-range access in synth_init()

commit ae428655 upstream.

Check that array index is in-bounds before accessing the synths[] array.
Signed-off-by: Nickolai Zeldovich <nickolai@csail.mit.edu>
Cc: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/staging/speakup/synth.c

@@ -342,7 +342,7 @@ int synth_init(char *synth_name)
 
 	mutex_lock(&spk_mutex);
 	/* First, check if we already have it loaded. */
-	for (i = 0; synths[i] != NULL && i < MAXSYNTHS; i++)
+	for (i = 0; i < MAXSYNTHS && synths[i] != NULL; i++)
 		if (strcmp(synths[i]->name, synth_name) == 0)
 			synth = synths[i];