powerpc/ps3: use dma_mapping_error()

The DMA address returned by dma_map_single() should be checked with
dma_mapping_error(). Fix the ps3stor_setup() function accordingly.

Fixes: 80071802cb ("[POWERPC] PS3: Storage Driver Core")
Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201213182622.23047-1-vincent.stehle@laposte.net

drivers/ps3/ps3stor_lib.c

@@ -189,7 +189,7 @@ int ps3stor_setup(struct ps3_storage_device *dev, irq_handler_t handler)
 	dev->bounce_lpar = ps3_mm_phys_to_lpar(__pa(dev->bounce_buf));
 	dev->bounce_dma = dma_map_single(&dev->sbd.core, dev->bounce_buf,
 					 dev->bounce_size, DMA_BIDIRECTIONAL);
-	if (!dev->bounce_dma) {
+	if (dma_mapping_error(&dev->sbd.core, dev->bounce_dma)) {
 		dev_err(&dev->sbd.core, "%s:%u: map DMA region failed\n",
 			__func__, __LINE__);
 		error = -ENODEV;