Allow drivers that use the nvmem API to read data stored on MTD devices.
For this the mtd devices are registered as read-only NVMEM providers.

We don't support device tree systems for now.
Signed-off-by: Alban Bedel <albeu@free.fr>
[Bartosz:
  - include linux/nvmem-provider.h
  - set the name of the nvmem provider
  - set no_of_node to true in nvmem_config
  - don't check the return value of nvmem_unregister() - it cannot fail
  - tweaked the commit message]
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>