egt-benchmark: Use gitsm fetcher

[kraj]

It houses hayai as a submodule, and it fails to build because hayai.h is missing. The reason is that the sources are not fetched properly. therefore use gitsm fetcher so it can fetch the hayai submodule and use it during build

Fixes './'`src/main.cpp src/main.cpp:7:10: fatal error: 'hayai.hpp' file not found ^~~ 1 error generated. make[1]: *** [Makefile:513: src/benchmark-main.o] Error 1

Signed-off-by: Khem Raj raj.khem@gmail.com

[noglitch]

I used @Dharma-B commit from kirkstone. Thanks for the heads-up!