ARM: dts: msm: disable HMSS clock source overriding for msm8996pro

HMSS cluster clock source overriding is not required during APM
switching or VDD_APCC voltage changes on MSM8996pro chips.
Therefore, disable this feature for the APM and PM8994 S11
regulator device nodes.

Change-Id: I201373867a8f07742f6bf2794fa59fc1c4c34d74
Signed-off-by: David Collins <collinsd@codeaurora.org>