prima_wlan: Fix Makefile so that module builds when pronto is selected

Change-Id: I1a5256402645ab260bc3733d2a154d5b0d2968b4
defconfig: Disable pronto BT-AMP

Per Qualcomm's Android.mk this shouldn't be enabled in Android.

It doesn't build, and it looks like it can't build on any
platform...

Change-Id: I23073f5439b018fbc4a30b33eab0f7012010d73c