Adds a dma_request_slave_channel_compat() wrapper which accepts
both the arguments from dma_request_channel() and
dma_request_slave_channel(). Based on whether the driver is
instantiated via DT, the appropriate channel request call will be
made.
This allows for a much cleaner migration of drivers to the
dmaengine DT API as platforms continue to be mixed between those
that boot using DT and those that do not.
Suggested-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Matt Porter <mporter@ti.com> Acked-by: Tony Lindgren <tony@atomide.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>