usb: gadget: udc: amd5536udc_pci fix null-ptr-dereference

init_dma_pools() calls dma_pool_create(...dev->dev) to create dma pool.
however, dev->dev is actually set after calling init_dma_pools(), which
effectively makes dma_pool_create(..NULL) and cause crash.
To fix this issue, init dma only after dev->dev is set.

[    1.317993] RIP: 0010:dma_pool_create+0x83/0x290
[    1.323257] Call Trace:
[    1.323390]  ? pci_write_config_word+0x27/0x30
[    1.323626]  init_dma_pools+0x41/0x1a0 [snps_udc_core]
[    1.323899]  udc_pci_probe+0x202/0x2b1 [amd5536udc_pci]

Fixes: 7c51247 (usb: gadget: udc: Provide correct arguments for 'dma_pool_create')
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Tong Zhang <ztong0001@gmail.com>
Link: https://lore.kernel.org/r/20210317230400.357756-1-ztong0001@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/udc/amd5536udc_pci.c

@@ -153,18 +153,18 @@ static int udc_pci_probe(
 	pci_set_master(pdev);
 	pci_try_set_mwi(pdev);
 
+	dev->phys_addr = resource;
+	dev->irq = pdev->irq;
+	dev->pdev = pdev;
+	dev->dev = &pdev->dev;
+
 	/* init dma pools */
 	if (use_dma) {
 		retval = init_dma_pools(dev);
 		if (retval != 0)
 			goto err_dma;
 	}
 
-	dev->phys_addr = resource;
-	dev->irq = pdev->irq;
-	dev->pdev = pdev;
-	dev->dev = &pdev->dev;
-
 	/* general probing */
 	if (udc_probe(dev)) {
 		retval = -ENODEV;