x86/Centaur: Report correct CPU/cache topology

Centaur CPUs enumerate the cache topology in the same way as Intel CPUs,
but the function is unused so for. The Centaur init code also misses to
initialize x86_info::max_cores, so the CPU topology can't be described
correctly.

Initialize x86_info::max_cores and invoke init_cacheinfo() to make
CPU and cache topology information available and correct.

Signed-off-by: David Wang <davidwang@zhaoxin.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: lukelin@viacpu.com
Cc: qiyuanwang@zhaoxin.com
Cc: gregkh@linuxfoundation.org
Cc: brucechang@via-alliance.com
Cc: timguo@zhaoxin.com
Cc: cooperyan@zhaoxin.com
Cc: hpa@zytor.com
Cc: benjaminpan@viatech.com
Link: https://lkml.kernel.org/r/1525314766-18910-4-git-send-email-davidwang@zhaoxin.com