ion: msm: Assume devicetree support

Remove support for passing parameters via platform_data now that
relevant targets use devicetree.

Change-Id: I2d8398163b5a4f358e257f416fd0e0c325664154
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
[isaacm@codeaurora.org: Relocated changes to correct file]
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>