fix: .gitignore to include memory tools

Added to .gitignore the following path, as it was
noticed as untracked after a TF-A CI run:
tools/memory/memory/__pycache__/

Signed-off-by: J-Alves <joao.alves@arm.com>
Change-Id: I35ba6f6a33593671c11f8e33c28545ae9bc57b4c
diff --git a/.gitignore b/.gitignore
index ac9a11d..e07d997 100644
--- a/.gitignore
+++ b/.gitignore
@@ -22,6 +22,7 @@
 tools/renesas/rzg_layout_create/*.elf
 tools/fiptool/fiptool
 tools/fiptool/fiptool.exe
+tools/memory/memory/__pycache__/
 tools/cert_create/src/*.o
 tools/cert_create/src/**/*.o
 tools/cert_create/cert_create