radv: use typed buffer loads for vertex input fetches

radv: use typed buffer loads for vertex input fetches

This drastically reduces the number of SGPRs because the driver
now uses descriptors per vertex binding, instead of per vertex
attribute format.

29077 shaders in 15096 tests
Totals:
SGPRS: 1354285 -> 1282109 (-5.33 %)
VGPRS: 909896 -> 908800 (-0.12 %)
Spilled SGPRs: 24840 -> 24811 (-0.12 %)
Code Size: 49221144 -> 48986628 (-0.48 %) bytes
Max Waves: 243930 -> 244229 (0.12 %)

Totals from affected shaders:
SGPRS: 390648 -> 318472 (-18.48 %)
VGPRS: 288432 -> 287336 (-0.38 %)
Spilled SGPRs: 94 -> 65 (-30.85 %)
Code Size: 11548412 -> 11313896 (-2.03 %) bytes
Max Waves: 86460 -> 86759 (0.35 %)

This gives a really tiny boost.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>