Staging: goldfish: use !x instead of x == NULL

Functions like devm_kzalloc, kmalloc_array, devm_ioremap,
usb_alloc_urb, alloc_netdev return NULL as a return value on failure.
Generally, When NULL represents failure, !x is commonly used.

This patch cleans up the tests on the results of these functions, thereby
using !x instead of x == NULL or NULL == x. This is done via following
coccinelle script:
@prob_7@
identifier x;
statement S;
@@

(
 x = devm_kzalloc(...);
|
 x = usb_alloc_urb(...);
|
 x = kmalloc_array(...);
|
 x = devm_ioremap(...);
|
 x = alloc_netdev(...);
)
 ...
- if(NULL == x)
+ if(!x)
        S
Further we have used isomorphism characteristics of coccinelle to
indicate x == NULL and NULL == x are equivalent. This is done via
following iso script.

Expression
@ is_null @ expression X; @@
X == NULL <=> NULL == X
Signed-off-by: Somya Anand <somyaanand214@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/goldfish/goldfish_audio.c

@@ -273,7 +273,7 @@ static int goldfish_audio_probe(struct platform_device *pdev)
 	dma_addr_t buf_addr;
 
 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
-	if (data == NULL)
+	if (!data)
 		return -ENOMEM;
 	spin_lock_init(&data->lock);
 	init_waitqueue_head(&data->wait);

drivers/staging/goldfish/goldfish_nand.c

@@ -330,7 +330,7 @@ static int goldfish_nand_init_device(struct platform_device *pdev,
 	mtd->priv = nand;
 
 	name = devm_kzalloc(&pdev->dev, name_len + 1, GFP_KERNEL);
-	if (name == NULL)
+	if (!name)
 		return -ENOMEM;
 	mtd->name = name;
 
@@ -383,7 +383,7 @@ static int goldfish_nand_probe(struct platform_device *pdev)
 		return -ENODEV;
 
 	base = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE);
-	if (base == NULL)
+	if (!base)
 		return -ENOMEM;
 
 	version = readl(base + NAND_VERSION);
@@ -399,7 +399,7 @@ static int goldfish_nand_probe(struct platform_device *pdev)
 
 	nand = devm_kzalloc(&pdev->dev, sizeof(*nand) +
 				sizeof(struct mtd_info) * num_dev, GFP_KERNEL);
-	if (nand == NULL)
+	if (!nand)
 		return -ENOMEM;
 
 	mutex_init(&nand->lock);