gpu: remove GHA target first then remove the obsoleted Makefile targets

Lets remove the GHA target actions first so the the follow-up PR tests are succeeding.

Fixes: #8900

Signed-off-by: Zvonko Kaiser <zkaiser@nvidia.com>

.github/workflows/build-kata-static-tarball-amd64.yaml

@@ -39,8 +39,6 @@ jobs:
           - kernel-dragonball-experimental
           - kernel-tdx-experimental
           - kernel-nvidia-gpu
-          - kernel-nvidia-gpu-snp
-          - kernel-nvidia-gpu-tdx-experimental
           - log-parser-rs
           - nydus
           - ovmf