CHG: [droid] do not h/w decode MP4 SD video (save on support)

Just a suggestion.
We can probably save on support by soft decoding mpeg2/mpeg4l2. 
H/W decoding of those does not bring anything (or some milliwatts saving) on modern devices, but quality/capabilities of them vary greatly.

We might add some check to be sure the device has the ponies (bogomips? #cpu?)

/cc @davilla