cpufreq: Save user policy min/max instead of policy min/max during hotplug

When a CPU is hotplugged off, various fields of the policy are saved so
that they can be restored when the CPU is hotplugged back in.

The existing code saves the policy min/max field during hotplug remove and
restores it into user policy min/max during hotplug add. This results in
the loss of the user policy min/max values across a hotplug remove/add.

Fix it by saving the user policy min/max instead of policy min/max during
hotplug remove. During a hotplug add, after user policy min/max is
restored, the policy min/max is already recomputed. So, there's no risk of
going beyound any limits imposed by the CPUFREQ_ADJUST/INCOMPATIBLE
notifiers.

Bug: 17889870
Change-Id: Ib8e09fa324c1f80f095c5754b5dcf2685e8e4a66
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Naveen Ramaraj <nramaraj@codeaurora.org>
cpufreq: Always allow update of user policy

In the cases where the system boots up in a constraint with policy min and
max lower than cpuinfo min/max, and user tries to set a higher user
policy min, the value would be overridden during the verifying the
limits.

Once user initiates the sysfs write the previous user policy is
maintained in policy min and max thus changing the limits for verification
of the current policy. Once the verification is completed restore the
current user policy min/max with the updated values if any. This would take
care of cases uwhere user policy min/max input is higher/lesser than the
current min and max.

Bug: 17889870
Change-Id: I5ad92ba05162cb5c32c3ba3fdae21d2e505493d3
Signed-off-by: Taniya Das <tdas@codeaurora.org>
Signed-off-by: Naveen Ramaraj <nramaraj@codeaurora.org>
Revert "Revert "Revert "hammerhead: Enable /dev/diag"""

Bug: 12134070

This reverts commit 56a0a3a049bef3ad23ecaf0c80ae95f36d7bd6be.
Merge with Google upstream

Signed-off-by: Muhammad Najmi Ahmad Zabidi <najmi.zabidi@gmail.com>