The fallback code in cpu_loop_exit_sigsegv is sufficient
for hppa linux-user.
Remove the code from cpu_loop that raised SIGSEGV.
This makes all of the code in mem_helper.c sysemu only,
so remove the ifdefs and move the file to hppa_softmmu_ss.
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>