nvmem: rockchip_efuse_regmap_config can be static

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>