msm: mdss: remove hw rev read from capability node

MDSS hardware capability node turns on clock and
check the hw revision every time client calls the
read operation. This is not required because MDSS
driver reads the revision information during MDP
driver probe.

Change-Id: I2db424f7aa1af5c5b006023f70516c2d83fe5372
Signed-off-by: Dhaval Patel <pdhaval@codeaurora.org>