cmd: upl: correct printf code

Building on 32-bit results in a build failure:

    cmd/upl.c:75:51: warning: format ‘%lx’ expects argument of type
    ‘long unsigned int’, but argument 3 has type ‘size_t’
    {aka ‘unsigned int’} [-Wformat=]
    75 | printf("UPL handoff written to %lx size %lx\n", addr, abuf_size(&buf));
       |                                         ~~^           ~~~~~~~~~~~~~~~
       |                                           |           |
       |                                           |           size_t {aka unsigned int}
       |                                           long unsigned int
       |                                         %x

Fixes: 264f4b0b34c0 ("upl: Add a command")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Neha Malcom Francis <n-francis@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/upl.c b/cmd/upl.c
index c974588..4996f36 100644
--- a/cmd/upl.c
+++ b/cmd/upl.c
@@ -72,7 +72,7 @@
 		return CMD_RET_FAILURE;
 	}
 	addr = map_to_sysmem(abuf_data(&buf));
-	printf("UPL handoff written to %lx size %lx\n", addr, abuf_size(&buf));
+	printf("UPL handoff written to %lx size %zx\n", addr, abuf_size(&buf));
 	if (env_set_hex("upladdr", addr) ||
 	    env_set_hex("uplsize", abuf_size(&buf))) {
 		printf("Cannot set env var\n");