doc: nvmem: Update example

Update the example to reflect the new API. I have chosen the brcm-nvram
driver since it seems to be simpler than the qfprom driver.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220220151527.17216-12-srinivas.kandagatla@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/driver-api/nvmem.rst

@@ -43,19 +43,20 @@ nvmem_device pointer.
 
 nvmem_unregister(nvmem) is used to unregister a previously registered provider.
 
-For example, a simple qfprom case::
+For example, a simple nvram case::
 
-  static struct nvmem_config econfig = {
-	.name = "qfprom",
-	.owner = THIS_MODULE,
-  };
-
-  static int qfprom_probe(struct platform_device *pdev)
+  static int brcm_nvram_probe(struct platform_device *pdev)
   {
+	struct nvmem_config config = {
+		.name = "brcm-nvram",
+		.reg_read = brcm_nvram_read,
+	};
 	...
-	econfig.dev = &pdev->dev;
-	nvmem = nvmem_register(&econfig);
-	...
+	config.dev = &pdev->dev;
+	config.priv = priv;
+	config.size = resource_size(res);
+
+	devm_nvmem_register(&config);
   }
 
 Users of board files can define and register nvmem cells using the