Staging: media: atomisp: Use kmalloc_array instead of kmalloc

Prefer kmalloc_array over kmalloc with multiply
because kmalloc_array performs additional checks
before memory allocation.

Fix the following issue reported by checkpatch.pl:
* WARNING: Prefer kmalloc_array over kmalloc with multiply
Signed-off-by: Georgiana Chelu <georgiana.chelu93@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/media/atomisp/pci/atomisp2/hmm/hmm_bo.c

@@ -725,7 +725,7 @@ static int alloc_private_pages(struct hmm_buffer_object *bo,
 
 	pgnr = bo->pgnr;
 
-	bo->page_obj = kmalloc(sizeof(struct hmm_page_object) * pgnr,
+	bo->page_obj = kmalloc_array(pgnr, sizeof(struct hmm_page_object),
 				GFP_KERNEL);
 	if (unlikely(!bo->page_obj)) {
 		dev_err(atomisp_dev, "out of memory for bo->page_obj\n");
@@ -990,13 +990,13 @@ static int alloc_user_pages(struct hmm_buffer_object *bo,
 	struct vm_area_struct *vma;
 	struct page **pages;
 
-	pages = kmalloc(sizeof(struct page *) * bo->pgnr, GFP_KERNEL);
+	pages = kmalloc_array(bo->pgnr, sizeof(struct page *), GFP_KERNEL);
 	if (unlikely(!pages)) {
 		dev_err(atomisp_dev, "out of memory for pages...\n");
 		return -ENOMEM;
 	}
 
-	bo->page_obj = kmalloc(sizeof(struct hmm_page_object) * bo->pgnr,
+	bo->page_obj = kmalloc_array(bo->pgnr, sizeof(struct hmm_page_object),
 		GFP_KERNEL);
 	if (unlikely(!bo->page_obj)) {
 		dev_err(atomisp_dev, "out of memory for bo->page_obj...\n");
@@ -1363,7 +1363,7 @@ void *hmm_bo_vmap(struct hmm_buffer_object *bo, bool cached)
 		bo->status &= ~(HMM_BO_VMAPED | HMM_BO_VMAPED_CACHED);
 	}
 
-	pages = kmalloc(sizeof(*pages) * bo->pgnr, GFP_KERNEL);
+	pages = kmalloc_array(bo->pgnr, sizeof(*pages), GFP_KERNEL);
 	if (unlikely(!pages)) {
 		mutex_unlock(&bo->mutex);
 		dev_err(atomisp_dev, "out of memory for pages...\n");