IB/hfi1: Replace kmalloc and memcpy with a kmemdup

This change was recommended by Coccinelle tool when I ran the command:
-bash-4.2$ make coccicheck MODE=patch M=drivers/infiniband/hw/hfi1/
Reviewed-by: Jubin John <jubin.john@intel.com>
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/staging/rdma/hfi1/efivar.c

@@ -125,13 +125,12 @@ static int read_efi_var(const char *name, unsigned long *size,
 	 * temporary buffer.  Now allocate a correctly sized
 	 * buffer.
 	 */
-	data = kmalloc(temp_size, GFP_KERNEL);
+	data = kmemdup(temp_buffer, temp_size, GFP_KERNEL);
 	if (!data) {
 		ret = -ENOMEM;
 		goto fail;
 	}
 
-	memcpy(data, temp_buffer, temp_size);
 	*size = temp_size;
 	*return_data = data;