irqchip/mvebu-gicp: Switch to devm_bitmap_zalloc()

Switch to devm_bitmap_zalloc() to show clearly what we are allocating.
Besides that it returns pointer of bitmap type instead of opaque void *.

Signed-off-by: Andy Shevchenko <[e-mail]>
Signed-off-by: Marc Zyngier <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/irqchip/irq-mvebu-gicp.c

···
 		gicp->spi_cnt += gicp->spi_ranges[i].count;
 	}
 
-	gicp->spi_bitmap = devm_kcalloc(&pdev->dev,
-				BITS_TO_LONGS(gicp->spi_cnt), sizeof(long),
-				GFP_KERNEL);
+	gicp->spi_bitmap = devm_bitmap_zalloc(&pdev->dev, gicp->spi_cnt, GFP_KERNEL);
 	if (!gicp->spi_bitmap)
 		return -ENOMEM;