nvmem: sprd: Add Spreadtrum SoCs eFuse support

The Spreadtrum eFuse controller is widely used to dump chip ID,
configuration setting, function select and so on, as well as
supporting one-time programming.

Signed-off-by: Freeman Liu <freeman.liu@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20191029114240.14905-8-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>