dmaengine: ti: drop of_match_ptr and mark of_device_id table as maybe unused

The driver can match only via the DT table so the main table should be
always used and the of_match_ptr does not have any sense (this also
allows ACPI matching via PRP0001, even though it is not relevant here).

The secondary match of_device_id tables (passed to of_match_node) should
be marked as maybe unused to fix compile testing (!CONFIG_OF on x86_64)
warnings:

    drivers/dma/ti/dma-crossbar.c:125:34: warning:
        ‘ti_am335x_master_match’ defined but not used [-Wunused-const-variable=]
    drivers/dma/ti/dma-crossbar.c:22:34: warning:
        ‘ti_dma_xbar_match’ defined but not used [-Wunused-const-variable=]
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20201120162303.482126-6-krzk@kernel.orgSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/ti/dma-crossbar.c

@@ -122,7 +122,7 @@ static void *ti_am335x_xbar_route_allocate(struct of_phandle_args *dma_spec,
 	return map;
 }
 
-static const struct of_device_id ti_am335x_master_match[] = {
+static const struct of_device_id ti_am335x_master_match[] __maybe_unused = {
 	{ .compatible = "ti,edma3-tpcc", },
 	{},
 };
@@ -292,7 +292,7 @@ static const u32 ti_dma_offset[] = {
 	[TI_XBAR_SDMA_OFFSET] = 1,
 };
 
-static const struct of_device_id ti_dra7_master_match[] = {
+static const struct of_device_id ti_dra7_master_match[] __maybe_unused = {
 	{
 		.compatible = "ti,omap4430-sdma",
 		.data = &ti_dma_offset[TI_XBAR_SDMA_OFFSET],
@@ -460,7 +460,7 @@ static int ti_dma_xbar_probe(struct platform_device *pdev)
 static struct platform_driver ti_dma_xbar_driver = {
 	.driver = {
 		.name = "ti-dma-crossbar",
-		.of_match_table = of_match_ptr(ti_dma_xbar_match),
+		.of_match_table = ti_dma_xbar_match,
 	},
 	.probe	= ti_dma_xbar_probe,
 };