dt-bindings: msm: Adding dsi ctrl and phy version strings

This changes adds the updated DSI Controller Version 2.4 string
and DSI PHY Version 4.1 string to the documentation for Kona.

Change-Id: Ie1059312417d6d9e3e5b60434d0e0dbdc20b4c73
Signed-off-by: Satya Rama Aditya Pinapala <psraditya30@codeaurora.org>