ARM: dts: msm: support qseecom bus scaling in msm8974

To support qseecom bus scaling, ab & ib values are changed to set four
bandwidth levels: "INACTIVE, LOW, MEDIUM and HIGH" with corresponding
bus bandwidth of {0M, 0M, 150M, 492M}; and the flag of support-bus-scaling
is also set.

Signed-off-by: Zhen Kong <zkong@codeaurora.org>