cpufreq: Remove unnecessary use of policy->shared_type

policy->shared_type field was added only for SoCs with ACPI support:

commit 3b2d99429e3386b6e2ac949fc72486509c8bbe36
Author: Venkatesh Pallipadi <venkatesh.pallipadi at intel.com>
Date:   Wed Dec 14 15:05:00 2005 -0500

    P-state software coordination for ACPI core

    http://bugzilla.kernel.org/show_bug.cgi?id=5737

Many non-ACPI systems are filling this field by mistake, which makes its usage
confusing. Lets clean it.

Signed-off-by: Viresh Kumar <viresh.kumar at linaro.org>
Cc: Linus Walleij <linus.walleij at linaro.org>
Cc: Stephen Warren <swarren at nvidia.com>
Cc: Shawn Guo <shawn.guo at linaro.org>
Cc: Santosh Shilimkar <santosh.shilimkar at ti.com>