ignore smatch generated files.

Change-Id: Id4f2d5c4ea2b4819b4634a8db6fe352b5e38e1f2

---

New to development and looking for tasks to work on to get familiar with
code, I noticed smatch generates some files at the root.  Since this
tool seems frequent for newbies like myself I thought it would be worth
getting rid of the chance of accidentally committing these files.
---
 .gitignore | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/.gitignore b/.gitignore
index 70ec6037fa7a..04472c37b6df 100644
--- a/.gitignore
+++ b/.gitignore
@@ -173,3 +173,11 @@ sphinx_*/
 
 # Rust analyzer configuration
 /rust-project.json
+
+# Smatch tree outputs
+smatch_compile.warns
+smatch_db.sqlite
+smatch_warns.txt
+smatch_warns.txt.caller_info
+smatch_warns.txt.sql
+trinity_smatch.[ch]
-- 
2.40.1.495.gc816e09b53d-goog