zink: set UBO alignments in nir_intrinsic_load_uniform lowering
resolves this error error: nir_intrinsic_align_offset(instr) < nir_intrinsic_align_mul(instr) (../src/compiler/nir/nir_validate.c:582) in ext_packed_depth_stencil-readdrawpixels piglit test
port of f5b14d98
I found this when looking into #2451 (closed) and the test now passes