[Bug target/77756] __get_cpuid() returns wrong values for level 7 (extended features)

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77756

--- Comment #7 from H.J. Lu <hjl.tools at gmail dot com> ---
Level 7 returns the maximum input value in EAX with ECX == 0.
Level 9 and 10 don't use ECX as input.
Level 11 takes ECX[7:0] as input level number.
Level 13 takes many values in ECX as input.
....

There is no fixed rule of ECX input for level >= 7.