x86: Drop unnecessary cpu code for TPL

We don't need to know every detail about the CPU in TPL. Drop some
superfluous functions to reduce code size. Add a simple CPU detection
algorithm which just supports Intel and AMD, since we only support TPL
on Intel, so far.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2 files changed