Just because someone dies away from his homeland, he is not regarded a martyr.
The martyr is the one who is killed during Jihad (fighting/striving in the cause of Allah) in a war between the Muslims and non-Muslims. There are other kinds of martyrs; namely one who dies of a stomach disease, one who dies of the plague, one who drowns, one who is crushed by a falling wall and a woman who dies in childbirth. Therefore, the one who dies while being away from his homeland is excluded from these types.May Allah grant us success. May peace and blessings of Allah be upon our Prophet Muhammad, his family and Companions!