ARM: dts: msm: Add BT node, GPIO regulator

Added BT node, PMIC GPIO 18 and 19 in the device tree

The BT chip on MSM8994 CDP board is powered via an external
regulator controlled by PM8994 GPIO 9. This external
regulator outputs a constant 3.3 V

Change-Id: Id8d159dad03664a38340b1d53af43474a17502e3
Signed-off-by: Vadivel Thekkamalai <vthekk@codeaurora.org>