dmaengine: ep93xx: Always start from BASE0

dmaengine: ep93xx: Always start from BASE0

BugLink: http://bugs.launchpad.net/bugs/1698799
commit 0037ae47812b1f431cc602100d1d51f37d77b61e upstream.

The current buffer is being reset to zero on device_free_chan_resources()
but not on device_terminate_all(). It could happen that HW is restarted and
expects BASE0 to be used, but the driver is not synchronized and will start
from BASE1. One solution is to reset the buffer explicitly in
m2p_hw_setup().

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>