Fix cache misalignment after network load operations

After any operation that downloads a file (e.g., pxe get, or dhcp), the
buffer containing the downloaded data is flushed.  This patch rounds
up the flushed size to a cacheline boundary, preventing a cache
misalignment message from u-boot.

Signed-off-by: Peter Chubb <peter.chubb@data61.csiro.au>

cmd/net.c

@@ -244,7 +244,7 @@ static int netboot_common(enum proto_t proto, cmd_tbl_t *cmdtp, int argc,
 	}
 
 	/* flush cache */
-	flush_cache(load_addr, size);
+	flush_cache(load_addr, ALIGN(size, CONFIG_SYS_CACHELINE_SIZE));
 
 	bootstage_mark(BOOTSTAGE_ID_NET_LOADED);