target/ppc: Move single-step check to ppc_tr_tb_stop

target/ppc: Move single-step check to ppc_tr_tb_stop

When single-stepping, force max_insns to 1 in init_disas
so that we exit the translation loop immediately.

Combine the single-step checks in tb_stop, and give the
gdb exception priority over the cpu exception, just as
we already do in gen_lookup_and_goto_ptr.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
Message-Id: <20210517205025.3777947-6-matheus.ferst@eldorado.org.br>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>