x86: include BMI1 and BMI2 in x86-64-v3 level

The "System V Application Binary Interface AMD64 Architecture Processor
Supplement" mandates the BMI1 and BMI2 CPU features for the x86-64-v3
level.

Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
(cherry picked from commit b80f16ad)