hw/cxl: Fix read from bogus memory

hw/cxl: Fix read from bogus memory

Peter and coverity report:

	We've passed '&data' to address_space_write(), which means "read
	from the address on the stack where the function argument 'data'
	lives", so instead of writing 64 bytes of data to the guest ,
	we'll write 64 bytes which start with a host pointer value and
	then continue with whatever happens to be on the host stack
	after that.

Indeed the intention was to write 64 bytes of data at the address given.

Fix the parameter to address_space_write().

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Link: https://lore.kernel.org/all/CAFEAcA-u4sytGwTKsb__Y+_+0O2-WwARntm3x8WNhvL1WfHOBg@mail.gmail.com/
Fixes: 6bda41a69bdc ("hw/cxl: Add clear poison mailbox command support.")
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Message-Id: <20240531-fix-poison-set-cacheline-v1-1-e3bc7e8f1158@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>