cpufreq: Avoid redundant target() calls for unchanged limits

cpufreq: Avoid redundant target() calls for unchanged limits

Drivers setting CPUFREQ_NEED_UPDATE_LIMITS expect target() to be
invoked even if the target frequency remains unchanged, so they can
update their internal policy limits state.

Currently the core invokes target() unconditionally whenever the
requested frequency matches policy->cur for such drivers, even if
policy->min and policy->max haven't changed since the previous update.

Track pending policy limit updates explicitly and skip redundant
target() invocations when neither the target frequency nor the
effective limits changed.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Lifeng Zheng <zhenglifeng1@huawei.com>
Reviewed-by: Zhongqiu Han <zhongqiu.han@oss.qualcomm.com>
Link: https://patch.msgid.link/d0107c364b709abca21acf88072220bc05478594.1779423281.git.viresh.kumar@linaro.org
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>