dmaengine: mmp_tdma: Remove the MMP_SRAM dependency

A generic SRAM will driver for Device Tree enabled platforms will do as
well.

The non-DT drivers that use mmp_tdma to transfer audio samples to and from
the audio SRAM should depend on MMP_SRAM themselves.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Link: https://lore.kernel.org/r/20200419164912.670973-8-lkundrak@v3.sk


Signed-off-by: Vinod Koul <vkoul@kernel.org>