Enable the use of python-config.sh in gdb-python config

Enable the use of python-config.sh in gdb-python configuration process.
Instead of hardcoding --with-python=yes, pass gdb_with_python to the
gdb-python config.

Change-Id: I0cb08c7f492f62d0a6c5aee3cdf145c1412b6f32
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/c/dsg-gnu/Internal/gnu-devtools-for-arm/+/733767


Reviewed-by: Gianluca Busiello <gianluca.busiello@arm.com>
Reviewed-by: Vaseeharan Vinayagamoorthy <vaseeharan.vinayagamoorthy@arm.com>
Tested-by: Service account - used by users in DSG GNU team <dgboter@arm.com>