dmaengine: ep93xx: Fix unsigned compared against 0

An unsigned value can never be negative,
so this test will always evaluate the same way.
In ep93xx_dma_alloc_chan_resources: An unsigned dma_cfg.port's
value is checked against EP93XX_DMA_I2S1 which is 0.

Signed-off-by: Advait Dhamorikar <advaitdhamorikar@gmail.com>
Link: https://lore.kernel.org/r/20241005093436.27728-1-advaitdhamorikar@gmail.com


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