msm: mdss: free the correct layer_list in compat_atomic_commit

layer_list is a pointer allocated based on the number of input_layers.
While freeing scale and pp related parameters for each layer, wrong
pointer is used instead of layer_list. Fix the typo to use the
correct pointer.

Change-Id: I7ab0fe42075ab5b4dfa5c73667f94fb8f0b5cc32
Signed-off-by: Shalini Krishnamoorthi <shakri@codeaurora.org>