fbdev: msm: set smmu cb domain attached during probe

Set the SMMU context-bank domain_attached flag during
MDP SMMU context-bank probe as the mapping/attach is
is handled by the SMMU driver during bootup.

Change-Id: I6ecc9ec695afe892a54c35d1afe6e4649fb60ccb
Signed-off-by: Nirmal Abraham <nabrah@codeaurora.org>