Dockerfile: Add missing 'rm -rf /tmp/coreboot-24.08'

We had missed removing the coreboot directory once done, fix this.

Signed-off-by: Tom Rini <trini@konsulko.com>

tools/docker/Dockerfile

@@ -296,7 +296,8 @@ RUN wget -O - https://coreboot.org/releases/coreboot-24.08.tar.xz | tar -C /tmp
     make olddefconfig && \
     make -j $(nproc) && \
     sudo mkdir /opt/coreboot && \
-    sudo cp build/coreboot.rom build/cbfstool /opt/coreboot/
+    sudo cp build/coreboot.rom build/cbfstool /opt/coreboot/ && \
+    rm -rf /tmp/coreboot-24.08
 
 # Create our user/group
 RUN echo uboot ALL=NOPASSWD: ALL > /etc/sudoers.d/uboot