tilapia: fetch grouper kernel

lol maybe a good idea to have the kernel source :p otherwise it will
fall back to the prebuilt one

Change-Id: I29cb1f1bd38498f2a31243f8d6e1760139cfb10a
tilapia: enable voice capability

for SIP calls in native dialer. GSM calls are blocked in radio level

Change-Id: I5f6e08fa38bd8ac6b3a74ef670cb7419f8c848a3