cxl/cxl-mailbox-utils: Fix size check for cmd_firmware_update_get_info

cxl/cxl-mailbox-utils: Fix size check for cmd_firmware_update_get_info

In the function cmd_firmware_update_get_info for handling Get FW info
command (0x0200h), the vmem, pmem and DC capacity size check were
incorrect. The size should be aligned to 256MiB, not smaller than
256MiB.

Signed-off-by: Fan Ni <fan.ni@samsung.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20241101132005.26633-2-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>