disp: msm: dsi: remove reg dump sub range

Remove the redundant register dump sub range
registration for DSI ctl/phy as it needs only
the base registration, since it is considered
as a single block.

Change-Id: I11546bfcde05d02849c53577c4546dcfa9203539
Signed-off-by: Veera Sundaram Sankaran <veeras@codeaurora.org>