mdss: dsi: Resolving memory leak in parse dsi commands

Free buf variable before exiting function in error cases
in order to avoid possible memory leaks.

Signed-off-by: Krishna Chaitanya Parimi <cparimi@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
ARM: VFP fix proc fs entry not loaded, FS still not online.