ide: move wait_hwif_ready() documentation in the right place

* Move wait_hwif_ready() documentation before this function.

* Fix trailing whitespaces.

* s/wait-for-busy/wait-for-non-busy/

* Remove no longer valid comment about the current code behavior.

* Docbook-ize it.

* Rename wait_hwif_ready() to ide_port_wait_ready().

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>