freedreno/ir3: avoid scheduler deadlock

freedreno/ir3: avoid scheduler deadlock

Deadlock can occur if we schedule an address register write, yet some
instructions which depend on that address register value also depend on
other unscheduled instructions that depend on a different address
register value.  To solve this, before scheduling an address register
write, ensure that all the other dependencies of the instructions which
consume this address register are already scheduled.

Signed-off-by: Rob Clark <robclark@freedesktop.org>