nvmem: core: set size for sysfs bin file

For some reason we never set the size for nvmem sysfs binary file.
Set this.

Reported-by: Gilles BULOZ <gilles.buloz@kontron.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20211130133909.6154-1-srinivas.kandagatla@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>