msm: msm_fb: Handle out of order msm_fb ioctls

Handle two cases when ioctls are received when they are not expected.
 - Writeback ioctls received when writeback (FB2) is not active.
 - Writeback ioctls received in random sequence when writeback (FB2)
   is active.

Change-Id: I54982e1aef09fd9c7df9354a139ac34219017951
Signed-off-by: Nirmal Abraham <nabrah@codeaurora.org>