dma: Allow TI_EDMA selectable for ARCH_KEYSTONE

Allow the TI_EDMA to be built for ARCH_KEYSTONE which also supports
the EDMA IP.

Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>