dmaengine/ste_dma40: allow memory buswidth/burst to be configured

Currently the runtime config implementation forces the memory side
parameters to be the same as the peripheral side. Allow these to be
different, and check for misconfiguration.

Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Reviewed-by: Ulf HANSSON <ulf.hansson@stericsson.com>
Tested-by: Stefan Nilsson <stefan.xk.nilsson@stericsson.com>
Reviewed-by: Per Forlin <per.forlin@stericsson.com>
Reviewed-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Cc: Robert Marklund <robert.marklund@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>