arm/dt: msm8974: Add Bus scaling configuration for BLSP1 UART2

PNOC bus client needs to vote for bus scaling. Hence add required
configuration of Bus scaling which is configured by HSLite driver.
Add required documentation for BUS Scaling with BLSP based HSUART.

Change-Id: If4f3fb798ac97f12d0990ac7470b9eb3b057bf2b
Signed-off-by: Mayank Rana <mrana@codeaurora.org>
1 file changed