kbuild: ignore all generated files for make allmodconfig (x86_64)

With following patch we now ignore all generated files for
make allmodconfig for x86_64.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/drivers/atm/.gitignore b/drivers/atm/.gitignore
new file mode 100644
index 0000000..a165b71
--- /dev/null
+++ b/drivers/atm/.gitignore
@@ -0,0 +1,5 @@
+# Ignore generated files
+fore200e_mkfirm
+fore200e_pca_fw.c
+pca200e.bin
+