nvmem: uniphier: add UniPhier eFuse driver

Add eFuse driver for Socionext UniPhier series SoC.
Note that eFuse device is under soc-glue and this register
implements as read only.

Signed-off-by: Keiji Hayashibara <hayashibara.keiji@socionext.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>