msm: mdss: avoid possible infinite loop on kmalloc failure

If any of the calls to kmalloc fail then the value of ret becomes
non-zero. Hence the code in the if condition gets executed. Then in
"exit" section ret is set again to non-zero value. The program jumps
back to the exit label and the code in the if condition gets executed
again leading to an infinite loop. Removing the goto exit line will
avoid the possible infinite loop forming when kmalloc fails.

Change-Id: I0d7d7d3d6d65806ede866667a7030fb9d1e0480e
Signed-off-by: Harsh Sahu <hsahu@codeaurora.org>