[PATCH] scripts: Fix potential null-deref

[Maks Mishin]

After having been compared to a NULL value at menu.c:799, 
pointer 'sym' is dereferenced at menu.c:812.

Signed-off-by: Maks Mishin <maks.mishinFZ at gmail.com>
---
 scripts/kconfig/menu.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
index 0fe7f3255a..c823719dfd 100644
--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -809,8 +809,10 @@ static void get_symbol_str(struct gstr *r, struct symbol *sym,
 			}
 		}
 	}
-	for_all_prompts(sym, prop)
-		get_prompt_str(r, prop, head);
+	if (sym) {
+		for_all_prompts(sym, prop)
+			get_prompt_str(r, prop, head);
+	}
 
 	prop = get_symbol_prop(sym);
 	if (prop) {
-- 
2.34.1