iar-docker-images: correct the package path

Change-Id: If5b6b0eb1593f9087cb77652b7d468fc8bd950c4
Signed-off-by: Arthur She <arthur.she@linaro.org>
diff --git a/jammy-amd64-tf-m-iar-build/tf-dependencies.install b/jammy-amd64-tf-m-iar-build/tf-dependencies.install
index 9b924a8..9d2002c 100755
--- a/jammy-amd64-tf-m-iar-build/tf-dependencies.install
+++ b/jammy-amd64-tf-m-iar-build/tf-dependencies.install
@@ -51,4 +51,4 @@
 /tmp/armclang-6.21/install_x86_64.sh --no-interactive --i-agree-to-the-contained-eula -d ${ARMCLANG_6_21_DIR}
 
 # Install IAR compiler
-dpkg -i ${IAR_PACKAGE}
+dpkg -i /tmp/${IAR_PACKAGE}