Remove unused MOONCAKE_COMPILE_ARG argument from Dockerfile (#35649)

docker/Dockerfile

@@ -17,8 +17,6 @@ ARG INSTALL_FLASHINFER_JIT_CACHE=0
 ARG FLASHINFER_VERSION=0.6.17
 ARG MOONCAKE_VERSION=0.3.12.post1
 ARG MSCCLPP_VERSION=sglang-v0.9.1
-#if need other arg please add in MOONCAKE_COMPILE_ARG
-ARG MOONCAKE_COMPILE_ARG="-DUSE_HTTP=ON -DUSE_MNNVL=ON -DUSE_CUDA=ON -DWITH_EP=ON"
 
 ENV DEBIAN_FRONTEND=noninteractive \
     CUDA_HOME=/usr/local/cuda \
@@ -418,7 +416,6 @@ ARG SGL_VERSION
 ARG USE_LATEST_SGLANG
 ARG GITHUB_ARTIFACTORY
 ARG MOONCAKE_VERSION
-ARG MOONCAKE_COMPILE_ARG
 ARG MSCCLPP_VERSION
 
 WORKDIR /sgl-workspace