powerpc/64s/exception: Re-inline some handlers

The reduction in interrupt entry size allows some handlers to be
re-inlined.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200225173541.1549955-18-npiggin@gmail.com