[RFC PATCH] dmaengine: xilinx_dma: Fix per-channel direction reporting via device_caps

[Rahul Navale]

From: Rahul Navale <rahul.navale at ifm.com>

Hi Folker,

>Could you test if this fixes your issue (and of course re-activate all the
<caps->assignments in dma_get_slave_caps(), keep the debug stuff for now)?

I applied the residue_granularity/has_sg gating patch you provided. I kept:
7e01511443c3 applied + RFC patch(xilinx_dma_device_caps + printk) +
dmaengine.c debug patch applied (dma_slave_caps_printk() + dump_stack()) +
all caps assignment in dma_get_slave_caps() enabled again.

The audio issue is not fixed. Playback still fails after the first buffer period.