drivers: pcie_ep: iproc: enable based on device tree specs

There are use cases for the pcie_ep driver where we don't
necessarily need the dma functionality. Added ifdef's around
the dma functionality so that it's only available if we
specify the dma engines in the device tree similar to

```
dmas = <&pl330 0>, <&pl330 1>;
dma-names = "txdma", "rxdma";
```

Signed-off-by: Tarun Karuturi <[email protected]>
Signed-off-by: Chris Friedt <[email protected]>
(cherry picked from commit 9d95f69)

Author: tarun292

drivers/pcie/endpoint/pcie_ep_iproc.c

@@ -475,9 +475,11 @@ static struct iproc_pcie_ep_config iproc_pcie_ep_config_0 = {
 	.map_low_size = DT_INST_REG_SIZE_BY_NAME(0, map_lowmem),
 	.map_high_base = DT_INST_REG_ADDR_BY_NAME(0, map_highmem),
 	.map_high_size = DT_INST_REG_SIZE_BY_NAME(0, map_highmem),
+#if DT_INST_NODE_HAS_PROP(0, dmas)
 	.pl330_dev = DEVICE_DT_GET(DT_INST_DMAS_CTLR_BY_IDX(0, 0)),
 	.pl330_tx_chan_id = DT_INST_DMAS_CELL_BY_NAME(0, txdma, channel),
 	.pl330_rx_chan_id = DT_INST_DMAS_CELL_BY_NAME(0, rxdma, channel),
+#endif
 };
 
 static struct pcie_ep_driver_api iproc_pcie_ep_api = {
@@ -487,7 +489,9 @@ static struct pcie_ep_driver_api iproc_pcie_ep_api = {
 	.unmap_addr = iproc_pcie_unmap_addr,
 	.raise_irq = iproc_pcie_raise_irq,
 	.register_reset_cb = iproc_pcie_register_reset_cb,
+#if DT_INST_NODE_HAS_PROP(0, dmas)
 	.dma_xfer = iproc_pcie_pl330_dma_xfer,
+#endif
 };
 
 DEVICE_DT_INST_DEFINE(0, &iproc_pcie_ep_init, NULL,