nir/opt_deref: Fix the vector bitcast optimization
It assumes the parent is a vector or scalar so we need to fail if it isn't.
Fixes: 9190f82d "nir/opt_deref: Add an optimization for bitcasts"
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It assumes the parent is a vector or scalar so we need to fail if it isn't.
Fixes: 9190f82d "nir/opt_deref: Add an optimization for bitcasts"