License tags of i2c-tools corrected

[Ondřej Lysoněk]

I reviewed the licensing of i2c-tools and found the License tags to be
inaccurate. I changed the tags as follows.

i2c-tools-eepromer subpackage:
License tag changed from
GPLv2+
to
GPLv2+ and Public Domain

python3-i2c-tools subpackage:
License tag changed from
GPLv2+
to
GPLv2

Best regards
Ondřej Lysoněk