[PATCH] sundance: solve host error problem in low performance embedded system when...

Solve host error problem in low performance embedded system when continune
down and up.  It will cause IP100A DMA TargetAbort.  So we need more safe
process to up and down IP100A with wait hardware completely stop and software
cur_tx/ dirty_tx/cur_task/last_tx be clear.

Signed-off-by: Jesse Huang <jesse@icplus.com.tw>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>