payton: Mount dsp at /vendor/lib/dsp [2/2]

* GSIs doesn’t have /dsp dir, they have a symlink to /vendor/lib/dsp
  in /dsp.

Change-Id: I4c2bbe460c22f6dc5533c93b23af1fc17b450e07
Signed-off-by: Erfan Abdi <erfangplus@gmail.com>