Add Optimize build flags

Signed-off-by: Seongmin Park <r_data@naver.com>

Conflicts:
	Makefile
	arch/arm/Makefile
Makefile: Add -mfpu=neon-vfpv4 and CFLAGS

Signed-off-by: Seongmin Park <r_data@naver.com>

Conflicts:
	Makefile
Makefile: Add -O2 options

Signed-off-by: Seongmin Park <r_data@naver.com>
Makefile: Add Optimize O3 level option

Signed-off-by: Seongmin Park <r_data@naver.com>

Conflicts:
	arch/arm/configs/franco2_mako_defconfig
Makefile: fix typo;;

Signed-off-by: Seongmin Park <r_data@naver.com>