of: unittest: fix warning on PowerPC frame size warning

The struct device variable "dev_bogus" was triggering this warning
on a PowerPC build:

    drivers/of/unittest.c: In function 'of_unittest_dma_ranges_one.constprop':
    [...] >> The frame size of 1424 bytes is larger than 1024 bytes
             [-Wframe-larger-than=]

This variable is now dynamically allocated.

Fixes: e0d07278 ("dma-mapping: introduce DMA range map, supplanting dma_pfn_offset")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Frank Rowand <frank.rowand@sony.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211210184636.7273-2-jim2101024@gmail.com

drivers/of/unittest.c

@@ -911,11 +911,18 @@ static void __init of_unittest_dma_ranges_one(const char *path,
 	if (!rc) {
 		phys_addr_t	paddr;
 		dma_addr_t	dma_addr;
-		struct device	dev_bogus;
+		struct device	*dev_bogus;
 
-		dev_bogus.dma_range_map = map;
-		paddr = dma_to_phys(&dev_bogus, expect_dma_addr);
-		dma_addr = phys_to_dma(&dev_bogus, expect_paddr);
+		dev_bogus = kzalloc(sizeof(struct device), GFP_KERNEL);
+		if (!dev_bogus) {
+			unittest(0, "kzalloc() failed\n");
+			kfree(map);
+			return;
+		}
+
+		dev_bogus->dma_range_map = map;
+		paddr = dma_to_phys(dev_bogus, expect_dma_addr);
+		dma_addr = phys_to_dma(dev_bogus, expect_paddr);
 
 		unittest(paddr == expect_paddr,
 			 "of_dma_get_range: wrong phys addr %pap (expecting %llx) on node %pOF\n",
@@ -925,6 +932,7 @@ static void __init of_unittest_dma_ranges_one(const char *path,
 			 &dma_addr, expect_dma_addr, np);
 
 		kfree(map);
+		kfree(dev_bogus);
 	}
 	of_node_put(np);
 #endif