nvmem: mediatek: Add Mediatek EFUSE driver

Add Mediatek EFUSE driver to access hardware data like
thermal sensor calibration or HDMI impedance.

Signed-off-by: Andrew-CT Chen <andrew-ct.chen@mediatek.com>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>