x86: Add support for more than 8 MTRRs

At present the mtrr command only support 8 MTRRs. Some SoCs have more than
that. Update the implementation to support up to 10. Read the number of
MTRRs dynamically instead.

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