tools: .gitignore: add asn1_compiler

Add the tool to the ignore list to prevent being marked as unversioned.

Signed-off-by: Dario Binacchi <dariobin@libero.it>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/tools/.gitignore b/tools/.gitignore
index d0176a7..82bdce2 100644
--- a/tools/.gitignore
+++ b/tools/.gitignore
@@ -1,3 +1,4 @@
+/asn1_compiler
 /atmel_pmecc_params
 /bin2header
 /bmp_logo