OK, so on my stopwatch, it takes 9.88 seconds.
john:~/Download/GIT/ti-linux-kernel-dev/KERNEL$ touch sound/soc/codecs/tlv320aic3x.c
john:~/Download/GIT/ti-linux-kernel-dev/KERNEL$ time make -j8 ARCH=arm LOCALVERSION=-ti-r33 CROSS_COMPILE="/home/john/Download/GIT/ti-linux-kernel-dev/dl/gcc-linaro-4.9-2015.05-x86_64_arm-linux-gnueabihf/bin/arm-linux-gnueabihf-" modules
CHK include/config/kernel.release
CHK include/generated/uapi/linux/version.h
CHK include/generated/utsrelease.h
make[1]: `include/generated/mach-types.h' is up to date.
CHK include/generated/bounds.h
CHK include/generated/asm-offsets.h
CALL scripts/checksyscalls.sh
CC [M] sound/soc/codecs/tlv320aic3x.o
LD [M] sound/soc/codecs/snd-soc-tlv320aic3x.o
Building modules, stage 2.
MODPOST 1940 modules
LD [M] sound/soc/codecs/snd-soc-tlv320aic3x.ko
real 0m9.879s
user 0m29.488s
sys 0m6.005s