package/pkg-generic.mk: move python fixup to generic package infrastructure

package/pkg-generic.mk: move python fixup to generic package infrastructure

Fixing _sysconfigdata*.{py,pyc} was previously done by python package
infrastructure. Some packages use python stuff without using python
package infrastructure.
These packages perform overwrites and need the specific python fixup
to fix them.

In order to be sure to fix all of these packages, the python fixup
is moved to the generic package infrastructure and applied to all
packages.
This follows the same principle as for the .la libtool files fixup.

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>