ci: Do not remove libgbm-dev

In order to enable container reuse in Virgl CI, keep libgbm-dev in the
container.

Signed-off-by: Rohan Garg <rohan.garg@collabora.com>
Reviewed-by: Emma Anholt <emma@anholt.net>
[cristian: discarded the update of MESA_IMAGE_TAG in debian/x86_build]

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Reviewed-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14413>

.gitlab-ci/container/debian/x86_build.sh

@@ -12,7 +12,6 @@ STABLE_EPHEMERAL=" \
       autotools-dev \
       bzip2 \
       cmake \
-      libgbm-dev \
       libtool \
       python3-pip \
       "
@@ -27,6 +26,7 @@ apt-get install -y --no-remove \
       libasan6 \
       libarchive-dev \
       libclang-cpp11-dev \
+      libgbm-dev \
       libglvnd-dev \
       libllvmspirvlib-dev \
       liblua5.3-dev \