cpufreq: conservative: Reset requested_freq on limits change

cpufreq: conservative: Reset requested_freq on limits change

A recently reported issue highlighted that the cached requested_freq
is not guaranteed to stay in sync with policy->cur. If the platform
changes the actual CPU frequency after the governor sets one (e.g.
due to platform-specific frequency scaling) and a re-sync occurs
later, policy->cur may diverge from requested_freq.

This can lead to incorrect behavior in the conservative governor.
For example, the governor may assume the CPU is already running at
the maximum frequency and skip further increases even though there
is still headroom.

Avoid this by resetting the cached requested_freq to policy->cur on
detecting a change in policy limits.

Reported-by: Lifeng Zheng <zhenglifeng1@huawei.com>
Tested-by: Lifeng Zheng <zhenglifeng1@huawei.com>
Link: https://lore.kernel.org/all/20260210115458.3493646-1-zhenglifeng1@huawei.com/
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Zhongqiu Han <zhongqiu.han@oss.qualcomm.com>
Cc: All applicable <stable@vger.kernel.org>
Link: https://patch.msgid.link/d846a141a98ac0482f20560fcd7525c0f0ec2f30.1773999467.git.viresh.kumar@linaro.org
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>