nvmem: sprd: Fix the block lock operation

nvmem: sprd: Fix the block lock operation

According to the Spreadtrum eFuse specification, we should write 0 to
the block to trigger the lock operation.

Fixes: 096030e7f449 ("nvmem: sprd: Add Spreadtrum SoCs eFuse support")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Freeman Liu <freeman.liu@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200323150007.7487-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>