Revert "usb: musb: use DMA mode 1 whenever possible"

This reverts commit 4f3e8d26.

it turns out that current implementation of Mode 1
DMA added a few regressions to some users, so we
need to revert this patch and let author work on
a better version of Mode 1 DMA support.

Signed-off-by: Felipe Balbi <balbi@ti.com>