nvmem: core: describe add missing dev function parameter

Document dev parameter which not described in devm_nvmem_unregister
and devm_nvmem_register functions.

Fix below warnings when kernel is compiled with W=1
drivers/nvmem/core.c:579: warning: Function parameter or member
 'dev' not described in 'devm_nvmem_register'
nvmem/core.c:615: warning: Function parameter or member 'dev'
 not described in 'devm_nvmem_unregister'
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/nvmem/core.c

@@ -569,6 +569,7 @@ static void devm_nvmem_release(struct device *dev, void *res)
  * nvmem_config.
  * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
  *
+ * @dev: Device that uses the nvmem device.
  * @config: nvmem device configuration with which nvmem device is created.
  *
  * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
@@ -607,6 +608,7 @@ static int devm_nvmem_match(struct device *dev, void *res, void *data)
  * devm_nvmem_unregister() - Unregister previously registered managed nvmem
  * device.
  *
+ * @dev: Device that uses the nvmem device.
  * @nvmem: Pointer to previously registered nvmem device.
  *
  * Return: Will be an negative on error or a zero on success.