x86/cacheinfo: Remove unused trace variable

15cd8812

 ("x86: Remove the CPU cache size printk's") removed the
last use of the trace local var. Remove it too and the useless trace
cache case.

No functional changes.

Reported-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230210234541.9694-1-bp@alien8.de
Link: http://lore.kernel.org/r/20220705073349.1512-1-jiapeng.chong@linux.alibaba.com