Add .vscode to gitignore

Given the popularity of vscode, .vscode is a directory that holds
the personal vscode preferences.

Signed-off-by: Mark Yacoub <markyacoub@chromium.org>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Reviewed-by: Petri Latvala <petri.latvala@intel.com>

.gitignore

@@ -50,3 +50,5 @@ results
 build
 patches
 Makefile
+
+.vscode