[mlir][bufferization] Remove `deallocationFn` from `BufferizationOptions` (#67128)

One-Shot Bufferize no longer deallocates buffers, so `deallocationFn`
can be removed.

Note: There is a `bufferization.dealloc_tensor` op that now always
bufferizes to `memref.dealloc`. This op will be phased out soon.