drivers/platform/x86: Use kmemdup

Use kmemdup when some other buffer is immediately copied into the
allocated region.

A simplified version of the semantic patch that makes this change is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
expression from,to,size,flag;
statement S;
@@

-  to = \(kmalloc\|kzalloc\)(size,flag);
+  to = kmemdup(from,size,flag);
   if (to==NULL || ...) S
-  memcpy(to, from, size);
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>

drivers/platform/x86/wmi.c

@@ -756,12 +756,10 @@ static __init acpi_status parse_wdg(acpi_handle handle)
 
 	total = obj->buffer.length / sizeof(struct guid_block);
 
-	gblock = kzalloc(obj->buffer.length, GFP_KERNEL);
+	gblock = kmemdup(obj->buffer.pointer, obj->buffer.length, GFP_KERNEL);
 	if (!gblock)
 		return AE_NO_MEMORY;
 
-	memcpy(gblock, obj->buffer.pointer, obj->buffer.length);
-
 	for (i = 0; i < total; i++) {
 		/*
 		  Some WMI devices, like those for nVidia hooks, have a