gemm+silu fused operator is not supported in ACL

[TianyuLi0]

Output of 'strings libarm_compute.so | grep arm_compute_version': arm_compute_version=v24.04 Build options: {'Werror': '1', 'build_dir': '//acl/build', 'debug': '0', 'neon': '1', 'opencl': '0', 'os': 'linux', 'openmp': '1', 'cppthreads': '0', 'arch': 'armv8.2-a', 'multi_isa': '1', 'fixed_format_kernels': '1', 'build': 'native'} Git hash=b'4fda7a803eaadf00ba36bd532481a33c18952089'

Platform: Neoverse N2

Operating System: Ubuntu 22.04

Problem description: gemm+silu fused operator is not supported in ACL

LLM use case: llama like models use silu activation with gemm.

Similar issue https://github.com/ARM-software/ComputeLibrary/issues/1083