msm: mdss: remove client from device list if failed to register

If there is any failure while registering a DBA client with MDSS
driver, then remove the client from device client list first and
then free the client. Otherwise driver might crash when
traversing the device client list in later stage, because of an
uninitialized entry in the list.

Change-Id: I60666f4c3dea5c7ea7b7c77bcb14b080ee25b54d
Signed-off-by: Sandeep Panda <spanda@codeaurora.org>