fs/pstore/ram_core.c: replace count*size kmalloc by kmalloc_array

kmalloc_array manages count*sizeof overflow.
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fs/pstore/ram_core.c

@@ -394,7 +394,7 @@ static void *persistent_ram_vmap(phys_addr_t start, size_t size)
 
 	prot = pgprot_noncached(PAGE_KERNEL);
 
-	pages = kmalloc(sizeof(struct page *) * page_count, GFP_KERNEL);
+	pages = kmalloc_array(page_count, sizeof(struct page *), GFP_KERNEL);
 	if (!pages) {
 		pr_err("%s: Failed to allocate array for %u pages\n",
 		       __func__, page_count);