Makefile: Add LTO Optimization

Link Time Optimization (LTO) gives GCC the capability of dumping its internal representation (GIMPLE) to disk, so that all the different compilation units that make up a single executable can be optimized as a single module. This expands the scope of inter-procedural optimizations to encompass the whole program (or, rather, everything that is visible at link time). More about LTO can be found here https://gcc.gnu.org/wiki/LinkTimeOptimization

Thanks @Cl3Kener

Signed-off-by: Lens-F <tnoah12@gmail.com>
soc: qcom: rq_stats: remove the redundant iowait check

Iowait_time check is redundant and it would lead to heavy load
due to miscaluculation of idle time. Hence remove this check
as iowait will considered based on io_busy flag.

[myfluxi: Adapt to msm 8960]

Change-Id: I4dd9f9c79205eca588daea8cc0fe892394a83391
CRs-fixed: 662052
Signed-off-by: Anji Jonnala <anjir@codeaurora.org>
Signed-off-by: Lens-F <tnoah12@gmail.com>