Disk led trigger: Forgot to add the file

I renamed the file and forgot to add it to the commit.
AXP_HWMON needs HWMON

Correction by patrickhwood
Add ledtrig_disk_activity() to sd.c
Merge branch 'pat-3.4.75-ct' of https://github.com/jnerin/linux-sunxi into pat-3.4.75-ct