ppc/pnv: Update skiboot to 7.1-106

This skiboot firmware importantly contains updates for HOMER/OCC bugs.
These subsystems have bitrotted in QEMU and skiboot and this update
allows new QEMU models to be exercised.

Power11 support is also added. This model is not yet merged in QEMU,
but firmware support will make development and testing simpler.

Signed-off-by: Nicholas Piggin <[email protected]>

Author: npiggin