tools: image-host.c: use correct output format

tools: image-host.c: use correct output format

When building on a 32bit host the following warning occurs:

tools/image-host.c: In function ‘fit_image_read_data’:
tools/image-host.c:310:42: warning: format ‘%ld’ expects argument of type
‘long int’, but argument 3 has type ‘ssize_t’ {aka ‘int’} [-Wformat=]
   printf("Can't read all file %s (read %ld bytes, expexted %ld)\n",
                                        ~~^
                                        %d
          filename, n, sbuf.st_size);
                    ~

n is of type ssize_t so we should use %zd for printing.

Fixes: 7298e422504e ("mkimage: fit: add support to encrypt image with aes")
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>