ALSA: Fix assignment of 0/1 to bool variables

Convert 0 to false and 1 to true when assigning values to bool
variables. Inspired by commit 3db1cd5c05f35fb43eb134df6f321de4e63141f2.

The simplified semantic patch that find this problem is as
follows (http://coccinelle.lip6.fr/):

@@
bool b;
@@
(
-b = 0
+b = false
|
-b = 1
+b = true
)

Signed-off-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 95558ef..44b0ba4 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -1151,14 +1151,14 @@
 	const char *names_to_check[] = {
 		"Headset", "headset", "Headphone", "headphone", NULL};
 	const char **s;
-	bool found = 0;
+	bool found = false;
 
 	if (strcmp("Speaker", kctl->id.name))
 		return;
 
 	for (s = names_to_check; *s; s++)
 		if (strstr(card->shortname, *s)) {
-			found = 1;
+			found = true;
 			break;
 		}