msm: acpuclock: support for OC on 7x30

Signed-off-by: Nathan Chan <e334cn@gmail.com>
msm: acpuclock: tweak performance and stability

Signed-off-by: Nathan Chan <e334cn@gmail.com>
acpuclock: fixed a weird issue that 1.5GHz not working for some devices

Signed-off-by: Nathan Chan <e334cn@gmail.com>