radv: make use of nir_move_out_const_to_consumer()

radv: make use of nir_move_out_const_to_consumer()

vkpipeline-db results:

Totals from affected shaders:
SGPRS: 28400 -> 28576 (0.62 %)
VGPRS: 27916 -> 27692 (-0.80 %)
Spilled SGPRs: 140 -> 138 (-1.43 %)
Spilled VGPRs: 0 -> 0 (0.00 %)
Private memory VGPRs: 0 -> 0 (0.00 %)
Scratch size: 0 -> 0 (0.00 %) dwords per thread
Code Size: 1534456 -> 1520560 (-0.91 %) bytes
LDS: 0 -> 0 (0.00 %) blocks
Max Waves: 3541 -> 3582 (1.16 %)
Wait states: 0 -> 0 (0.00 %)

Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>