gb_en is the identifier for British English (Great Britain _ ENglish). Which makes me highly doubt it is related to any sort of malicious activity.
Doing some google's, aside from the usage I'm familiar with, the .smd is sometimes used to store updated Flash BIOS and system software on some mobile devices. As part of the boot process, the "normal" system software will look for the file, and if it finds it for it's defined locale it will load it. This file is probably added by whatever software you use in conjunction with the phone on your machine, which likely checks for the latest version and plops it down as a file on the device each time. (It's also possible that the phone protects it in some manner, by rewriting it if it is deleted)