msm: kgsl: Protect CP_STATE_DEBUG_INDEX

Put CP_STATE_DEBUG_INDEX and CP_STATE_DEBUG_DATA under protection
to keep it from being written from an IB1. Doing so however opens
up a subtle "feature" in the microcode: memory read opcodes turn off
protected mode in the microcode to do the read and then turns it
back on regardless of the initial state. This is a problem if the
memory read happens while protected mode is turned off and then we
try to access a protected register which then complains and goes boom.

To account for this irregularity explicitly turn back off protected
mode in all the places where we know this will be a problem.