iio/accel/kxsd9_i2c: no license, taints kernel

[Randy Dunlap]

[44583.951806] kxsd9_i2c: module license 'unspecified' taints kernel.
[44583.951931] kxsd9_i2c: Unknown symbol __devm_regmap_init_i2c (err 0)

__devm_regmap_i2c() is EXPORT_SYMBOL_GPL(), so a non-compatible license
cannot use it.

-- 
~Randy