msm: usbaudio: Fix memory allocation for USB audio module init

Fix memory allocation issue in snd_usb_audio_init()
use sizeof(struct) insead of sizeof(pointer)

Change-Id: I270bbd7111e97dd4e0e92378f61d5025e16f5fca
Signed-off-by: Alex Fradkin <afradkin@codeaurora.org>
diff --git a/sound/usb/card.c b/sound/usb/card.c
index 1452312..deeb5c7 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -723,7 +723,7 @@
 		return -EINVAL;
 	}
 
-	usbaudiosdev = kzalloc(sizeof(usbaudiosdev), GFP_KERNEL);
+	usbaudiosdev = kzalloc(sizeof(*usbaudiosdev), GFP_KERNEL);
 	usbaudiosdev->name = "usb_audio";
 
 	err = switch_dev_register(usbaudiosdev);