msm: mdss: send svs plus request to rpm for certain freqs

Add rpm vote to enable/disable SVS plus level when mdp is between
166mhz-267mhz. This helps keep mdp power low without reaching nominal.

Crs-Fixed: 849721
Change-Id: If3bdf9daa82cade4f3564bc28a630f63c53691e2
Signed-off-by: Siddhartha Agrawal <agrawals@codeaurora.org>