msm: camera: isp: Add Phy source for CPHY TPG

Add Phy selection logic if PHY TPG is enabled. Add phy resource 
in case of external TPG.

CRs-Fixed: 2787956
Change-Id: Ib9d827dc411965d8dd849de53932c62c9b4a4a02
Signed-off-by: Chandan Kumar Jha <cjha@codeaurora.org>