Makefile: re-add JustArchi GCC flags.
except -ftrace (to keep the kernel a bit smaller) and -fdata-sections (reboot issues)

ref commit: https://github.com/JustArchi/android_build/commit/8e1b82c082a8de9160e6c0fc3ded37b591c3e517
fix build with Linaro GCC 4.9.1

Conflicts:
	drivers/cpufreq/cpufreq_intelliactive.c
fix build with Linaro GCC 4.9.1

Conflicts:
	drivers/net/wireless/bcmdhd/dhd_linux.c
	drivers/net/wireless/bcmdhd/wl_cfg80211.c
	drivers/net/wireless/bcmdhd/wl_cfgp2p.c
fix build warnings to compile with linaro -Ofast optimization

Conflicts:
	drivers/power/pm8921-bms-htc.c
	drivers/power/pm8921-charger-htc.c