The mcp47feb02_parse_fw() function uses data->lock, but the mutex was
initialized after this function in probe path.
Since mcp47feb02_parse_fw() is only called from probe(), remove the lock.
Fixes: bf394cc803 ("iio: dac: adding support for Microchip MCP47FEB02")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>