powerpc/64/interrupt: avoid BUG/WARN recursion in interrupt entry

powerpc/64/interrupt: avoid BUG/WARN recursion in interrupt entry

BUG/WARN are handled with a program interrupt which can turn into an
infinite recursion when there are bugs in interrupt handler entry
(which can be irritated by bugs in other parts of the code).

There is one feeble attempt to avoid this recursion, but it misses
several cases. Make a tidier macro for this and switch most bugs in
the interrupt entry wrapper over to use it.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220926054305.2671436-7-npiggin@gmail.com