Staging: line6: fix up NULL assignment mistakes

Should use NULL for a pointer, not 0, otherwise sparse complains.

Cc: Markus Grabner <grabner@icg.tugraz.at>
Cc: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/line6/midibuf.c b/drivers/staging/line6/midibuf.c
index 1f5934e..5726bb1 100644
--- a/drivers/staging/line6/midibuf.c
+++ b/drivers/staging/line6/midibuf.c
@@ -44,7 +44,7 @@
 {
 	this->buf = (unsigned char *)kmalloc(size, GFP_KERNEL);
 
-	if(this->buf == 0)
+	if (this->buf == NULL)
 		return -ENOMEM;
 
 	this->size = size;
@@ -261,8 +261,6 @@
 
 void midibuf_destroy(struct MidiBuffer *this)
 {
-	if(this->buf != 0) {
-		kfree(this->buf);
-		this->buf = 0;
-	}
+	kfree(this->buf);
+	this->buf = NULL;
 }