msm: mdss: Free allocated layer pp_info when scalar copy fails

During atomic commit ioctl, the pp_info and scale data structures
are deep-copied in to kernel structures. If the scale data is failing
to copy, the kernel pp_info structure needs to be freed before exiting
with error.

Change-Id: Ia51f27c288dd88bb36311eae073294208259b71f
Signed-off-by: Benet Clark <benetc@codeaurora.org>