common: Use new numeric setenv functions

Use setenv_ulong(), setenv_hex() and setenv_addr() in common/

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/cmd_ximg.c b/common/cmd_ximg.c
index 42a7eba..ea0a26e 100644
--- a/common/cmd_ximg.c
+++ b/common/cmd_ximg.c
@@ -50,7 +50,6 @@
 	ulong		data, len, count;
 	int		verify;
 	int		part = 0;
-	char		pbuf[10];
 	image_header_t	*hdr;
 #if defined(CONFIG_FIT)
 	const char	*uname = NULL;
@@ -256,10 +255,8 @@
 		puts("OK\n");
 	}
 
-	sprintf(pbuf, "%8lx", data);
-	setenv("fileaddr", pbuf);
-	sprintf(pbuf, "%8lx", len);
-	setenv("filesize", pbuf);
+	setenv_hex("fileaddr", data);
+	setenv_hex("filesize", len);
 
 	return 0;
 }