cmd: efi: Fix wrong memory descriptor end address

Each entry of the EFI memory descriptors occupies map->desc_size,
not sizeof(struct efi_mem_desc).

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

cmd/efi.c

@@ -83,7 +83,7 @@ void *efi_build_mem_table(struct efi_entry_memmap *map, int size, bool skip_bs)
 	prev = NULL;
 	addr = 0;
 	dest = base;
-	end = base + count;
+	end = (struct efi_mem_desc *)((ulong)base + count * map->desc_size);
 	for (desc = base; desc < end; desc = efi_get_next_mem_desc(map, desc)) {
 		bool merge = true;
 		int type = desc->type;