DMAENGINE: Remove stedma40_set_psize and pre_transfer hook in ste_dma40

Remove obsolete pre_transfer hook in stedma40_chan_cfg. The
intent of this hook is merely to handle burst size
compensation for ux500 variant MMCI. Remove obsolete stedma40_set_psize
since it is only called from pre_transfer. DMAEngine device_control
replaces the functionality of stedma40_set_psize.

Signed-off-by: Per Forlin <per.forlin@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>