The recent revert of 8ca78eb03fd4 removed the guards around these calls.
As a result, LINT builds for architectures which do not implement this
API on the branch are failing -- armv7, powerpc, powerpc64, riscv.
This is a direct commit to stable/13.
Fixes: fa6603d4a725 (Revert "LinuxKPI: Make FPU sections thread-safe...)