Commit c93f261d ("Documentation/core-api: add swiotlb documentation")
accidentally refers to CONFIG_DYNAMIC_SWIOTLB in one place, while the
config is actually called CONFIG_SWIOTLB_DYNAMIC.

Correct the reference to the intended config option.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@redhat.com>
Reviewed-by: Petr Tesarik <petr@tesarici.cz>
Signed-off-by: Christoph Hellwig <hch@lst.de>