msm: mdss: Check if histogram has been disabled in collect

Before setting the histogram back to read or idle, check if
the histogram has been disabled to prevent state corruption.

Change-Id: Ibe3d274077189a96358a75cbd7ac2687aabe9ea4
Signed-off-by: Benet Clark <benetc@codeaurora.org>
msm: mdss: Move histogram disable complete_all after intr disable

Previously, complete_all was called during histogram disablement before
the histogram interrupts were disabled, which can lead to issues if an
interrupt comes in between complete_all and interrupt disablement. Now
complete_all is called afterwards, which guarantees no more interrupts
will come.

Change-Id: I831a01ce8433470b337a42a644d98ab5807fdbd7
Signed-off-by: Benet Clark <benetc@codeaurora.org>