disp: msm: dp: adding prefix for logs

Adding prefixes for error, debug and info
messages in dp files. To enable debug logs
run "echo 0x100 > /sys/module/drm/parameters/debug"

CRs-Fixed: 2493739
Change-Id: Ibf509e837f527be6bff6b7a1c34b0cde2921b388
Signed-off-by: Satya Rama Aditya Pinapala <psraditya30@codeaurora.org>