media: staging: media: Make use of devm_platform_ioremap_resource

Fix below issue reported by coccicheck
drivers/staging//media/omap4iss/iss.c:915:1-15: WARNING: Use
devm_platform_ioremap_resource for iss -> regs [ res ]

Signed-off-by: Hariprasad Kelam <hariprasad.kelam@gmail.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/staging/media/omap4iss/iss.c

@@ -908,11 +908,7 @@ static int iss_map_mem_resource(struct platform_device *pdev,
 				struct iss_device *iss,
 				enum iss_mem_resources res)
 {
-	struct resource *mem;
-
-	mem = platform_get_resource(pdev, IORESOURCE_MEM, res);
-
-	iss->regs[res] = devm_ioremap_resource(iss->dev, mem);
+	iss->regs[res] = devm_platform_ioremap_resource(pdev, res);
 
 	return PTR_ERR_OR_ZERO(iss->regs[res]);
 }