DMAENGINE: ste_dma40: fix suspend bug

This fixes a bug when suspending channels: first make the checks,
then suspend the channel, not the other way around.

Signed-off-by: Jonas Aaberg <jonas.aberg@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>