arm64: add ARCH_HAS_OPP to allow enabling OPP library

The Operating Performance Point (OPP) Layer library is a generic
library used by CPUFREQ and DEVFREQ. It can be enabled only on the
platforms that specify ARCH_HAS_OPP option.

This patch selects that option in order to allow ARM64 based platforms
to use OPP library.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Git-commit: 333d17e566192efda500769fb55b11da71c6d960
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>