nvmem: jz4780-efuse: Use PTR_ERR_OR_ZERO() to simplify code

Fixes coccicheck warning:

drivers/nvmem/jz4780-efuse.c:214:1-3: WARNING: PTR_ERR_OR_ZERO can be used

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Samuel Zou <zou_wei@huawei.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200511145042.31223-4-srinivas.kandagatla@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>