Staging: kpc2000: kpc_dma: Remove comparison to NULL.

Comparison to NULL been used across the driver,
remove them and use (!var) instead.

Checkpatch.pl: CHECK:
Comparison to NULL could be written "!desc"... etc
Signed-off-by: Sam Muhammed <jane.pnx9@gmail.com>
Link: https://lore.kernel.org/r/f344afba0a8bb0413941a63678688435f04a96b4.1585143581.git.jane.pnx9@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/kpc2000/kpc_dma/dma.c

@@ -236,7 +236,7 @@ int  count_descriptors_available(struct kpc_dma_device *eng)
 	struct kpc_dma_descriptor *cur = eng->desc_next;
 
 	while (cur != eng->desc_completed) {
-		BUG_ON(cur == NULL);
+		BUG_ON(!cur);
 		count++;
 		cur = cur->Next;
 	}

drivers/staging/kpc2000/kpc_dma/fileops.c

@@ -124,7 +124,7 @@ static int kpc_dma_transfer(struct dev_private_data *priv,
 		pcnt = count_parts_for_sge(sg);
 		for (p = 0 ; p < pcnt ; p++) {
 			// Fill out the descriptor
-			BUG_ON(desc == NULL);
+			BUG_ON(!desc);
 			clear_desc(desc);
 			if (p != pcnt-1) {
 				desc->DescByteCount = 0x80000;
@@ -203,11 +203,11 @@ void  transfer_complete_cb(struct aio_cb_data *acd, size_t xfr_count, u32 flags)
 {
 	unsigned int i;
 
-	BUG_ON(acd == NULL);
-	BUG_ON(acd->user_pages == NULL);
-	BUG_ON(acd->sgt.sgl == NULL);
-	BUG_ON(acd->ldev == NULL);
-	BUG_ON(acd->ldev->pldev == NULL);
+	BUG_ON(!acd);
+	BUG_ON(!acd->user_pages);
+	BUG_ON(!acd->sgt.sgl);
+	BUG_ON(!acd->ldev);
+	BUG_ON(!acd->ldev->pldev);
 
 	for (i = 0 ; i < acd->page_count ; i++) {
 		if (!PageReserved(acd->user_pages[i])) {

drivers/staging/kpc2000/kpc_dma/kpc_dma_driver.h

@@ -198,14 +198,14 @@ u32  GetEngineCompletePtr(struct kpc_dma_device *eng)
 static inline
 void  lock_engine(struct kpc_dma_device *eng)
 {
-	BUG_ON(eng == NULL);
+	BUG_ON(!eng);
 	mutex_lock(&eng->sem);
 }
 
 static inline
 void  unlock_engine(struct kpc_dma_device *eng)
 {
-	BUG_ON(eng == NULL);
+	BUG_ON(!eng);
 	mutex_unlock(&eng->sem);
 }