cpuid-x86: Fix duplicate asm labels in case of heavy inlining on x86-32

hwloc_x86_discover() calls hwloc_look_x86() twice, which calls hwloc_have_x86_cpuid().
If everything gets inlined, the asm label inside hwloc_have_x86_cpuid()
is duplicated.
Use a local label with f annotation in jumps to avoid the problem.

Thanks to Thomas Van Doren for reporting the issue (found with gcc -m32).

(cherry picked from commit 50e447f5bc6db88aefdc2f7e55dd43c6f575c870)