Revert "cpufreq: brcmstb-avs-cpufreq: add check for cpufreq_cpu_get's return value"

This reverts commit d951cf51 which is
commit f661017e upstream.

It breaks the Android kernel build and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: If757d9acc2096adb98e44845ca21e6cfa67350bd
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>