SYCL: Introducing memory host pool (llama/11251)

SYCL: Introducing memory host pool (llama/11251)

* Implement host pool for matrix_info

Creating a new memory pool on the host to store memory location for
matrix_info needed to launch gemm_batch from oneMKL/oneMath.
Removing complex support in gemm_batch since it is not used in llama.cpp

* Remove unnecessary headers and cast

* Reorder member variable to avoid warning on initialization

* Formatting

* Remove unused variable

* Address PR review feedback - remove warning

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Signed-off-by: nscipione <redacted>