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

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