Fix implicit declaration of function 'GAP_BleReadPeerPrefConnParams' warning.

Change-Id: Ib7413ba8627e193e9b43f8a906d24d4a0856d173
Fixing a lot of build warnings, mostly impliciate declaration of functions.

Change-Id: I2257893f65ed8c25d4fade2e0fa66f077e808b75