amd64: Call clock_init() after finishidentcpu()

As in commit c3d830cf7c71, we should finalize CPU identification before
probing the TSC frequency.

Fixes: 84369dd52369 ("x86: Probe the TSC frequency earlier")
Reported by: khng

(cherry picked from commit f7a6dccf426676bdd8c6be25491e57dca830de25)