fix: static-checks-cpu-erratum-order.py

Current static-checks-cpu-erratum-order.py checks for all files
but when a CPU file is deleted we ned to ignore static check for
those files. Add git diff-filter

Use filter "--diff-filter=ACMRT"

Considers files -
A = Added
C = Copied
M = Modified
R = Renamed
T = Type changed
(skips D = Deleted)

Change-Id: Ie982a681913720b2814947d82e0438a233e140e3
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
diff --git a/script/static-checks/static-checks-cpu-erratum-order.py b/script/static-checks/static-checks-cpu-erratum-order.py
index 2b2d2f0..8b08220 100755
--- a/script/static-checks/static-checks-cpu-erratum-order.py
+++ b/script/static-checks/static-checks-cpu-erratum-order.py
@@ -299,6 +299,7 @@
             "git",
             "diff",
             "--name-only",
+            "--diff-filter=ACMRT",
             base_commit + ".." + end_commit,
             "lib/cpus/aarch64/"
         ],