tf-a: style: remove block chomping indicator

Keep consistency. The block chomping indicator isn't necessary.

Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>
Change-Id: I2a5bd9248d44e8ebe5d839f4f8675aed94048065
diff --git a/tf-main.yaml b/tf-main.yaml
index c73a6db..f983611 100644
--- a/tf-main.yaml
+++ b/tf-main.yaml
@@ -81,7 +81,7 @@
       - workspace-cleanup
       - timestamps
     builders:
-    - shell: |-
+    - shell: |
         #!/bin/bash
 
         set -e