ARM: dts: msm: add bg-speaker-connected property on msm8909w

On msm8909w targets speaker usage is optional. If speaker is
not connected, no need to send smart pa init params to BG.
So add property to ensure speaker is connected to target.
This property can be defined based on the speaker
connections/requirement.

Change-Id: I5e22e8e9f44c82bb17b5e87677bd0efcff65fefa
Signed-off-by: Bala Kishore Pati <balakishorepati@codeaurora.org>