4c4e6232ee
Was hitting an assert with vs-varying-array-mat4-index-col-row-wr.shader_test
When eliminating a copy, we were dropping the use_count of the mov that
is skipped, but not increasing the use_count of it's src instruction.
Fixes: 76440fcca9 freedreno/ir3: clean up dangling false-dep's
Signed-off-by: Rob Clark <robdclark@gmail.com>