vl: Use size_t for sizes in get_boot_devices_list()

Code mixes uint32_t, int and size_t.  Very unlikely to go wrong in
practice, but clean it up anyway.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/hw/fw_cfg.c b/hw/fw_cfg.c
index 699383c..3b31d77 100644
--- a/hw/fw_cfg.c
+++ b/hw/fw_cfg.c
@@ -471,7 +471,7 @@
 
 static void fw_cfg_machine_ready(struct Notifier *n, void *data)
 {
-    uint32_t len;
+    size_t len;
     FWCfgState *s = container_of(n, FWCfgState, machine_ready);
     char *bootindex = get_boot_devices_list(&len);
 
diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index cd12f09..6599617 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -179,7 +179,7 @@
 
 void add_boot_device_path(int32_t bootindex, DeviceState *dev,
                           const char *suffix);
-char *get_boot_devices_list(uint32_t *size);
+char *get_boot_devices_list(size_t *size);
 
 bool usb_enabled(bool default_usb);
 
diff --git a/vl.c b/vl.c
index f4cf7e8..4ee1302 100644
--- a/vl.c
+++ b/vl.c
@@ -1198,15 +1198,15 @@
  * memory pointed by "size" is assigned total length of the array in bytes
  *
  */
-char *get_boot_devices_list(uint32_t *size)
+char *get_boot_devices_list(size_t *size)
 {
     FWBootEntry *i;
-    uint32_t total = 0;
+    size_t total = 0;
     char *list = NULL;
 
     QTAILQ_FOREACH(i, &fw_boot_order, link) {
         char *devpath = NULL, *bootpath;
-        int len;
+        size_t len;
 
         if (i->dev) {
             devpath = qdev_get_fw_dev_path(i->dev);