[PATCH] device_tree: Fix compiler error

[Stefan Weil]

A build with gcc (Debian 10.2.1-6) 10.2.1 20210110 fails:

../../../softmmu/device_tree.c: In function ‘qemu_fdt_add_path’:
../../../softmmu/device_tree.c:560:18: error: ‘retval’ may be used 
uninitialized in this function [-Werror=maybe-uninitialized]
  560 |     int namelen, retval;
      |                  ^~~~~~

This is not a real error, but the compiler can be satisfied with a small change.

Fixes: b863f0b75852 ("device_tree: Add qemu_fdt_add_path")
Signed-off-by: Stefan Weil <sw@weilnetz.de>
---
 softmmu/device_tree.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c
index 3965c834ca..9e96f5ecd5 100644
--- a/softmmu/device_tree.c
+++ b/softmmu/device_tree.c
@@ -564,7 +564,7 @@ int qemu_fdt_add_path(void *fdt, const char *path)
         return -1;
     }
 
-    while (p) {
+    do {
         name = p + 1;
         p = strchr(name, '/');
         namelen = p != NULL ? p - name : strlen(name);
@@ -584,7 +584,7 @@ int qemu_fdt_add_path(void *fdt, const char *path)
         }
 
         parent = retval;
-    }
+    } while (p);
 
     return retval;
 }
-- 
2.30.2