tools/python: mismatch between pyxc_methods flags and PyObject definitions

tools/python: mismatch between pyxc_methods flags and PyObject definitions

pygrub in xen-4.13.0 with python 3.8.2 fails with the error

Traceback (most recent call last):
  File "/usr/libexec/xen/bin/pygrub", line 21, in <module>
    import xen.lowlevel.xc
SystemError: bad call flags

This patch fixes mismatches in tools/python/xen/lowlevel/xc/xc.c
between the flag bits defined in pyxc_methods and the parameters passed
to the corresponding PyObject definitions.

With this patch applied pygrub works as expected.

Signed-off-by: Michael Young <m.a.young@durham.ac.uk>
Reviewed-by: Wei Liu <wl@xen.org>
Acked-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>