tool build: Remove __get_cpuid feature test

tool build: Remove __get_cpuid feature test

This feature test is no longer used so remove.

The function tested by the feature test is used in:
tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
however, the Makefile just assumes the presence of the function and
doesn't perform a build feature test for it.

Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>