powerpc/watchpoints: Don't track info persistently

info is cheap to retrieve, and is likely optimised by the compiler
anyway. On the other hand, propagating it across the functions makes it
possible to be inconsistent and adds needless complexity.

Remove it, and invoke counter_arch_bp() when we need to work with it.

As we don't persist it, we just use the local bp array to track whether
we are ignoring a breakpoint.

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230801011744.153973-3-bgray@linux.ibm.com