msm: sde: Fix SDE rotator driver error handling

Initialize some local variables before using them and safely return
an error code when encounter error cases in the SDE rotator driver.

CRs-Fixed: 1060558
Change-Id: I25406b13ac2007f1789d8d32e428c39dac4c29cf
Signed-off-by: Benjamin Chan <bkchan@codeaurora.org>
Signed-off-by: Narendra Muppalla <NarendraM@codeaurora.org>