radv/llvm,aco: always split typed vertex buffer loads on GFX6 and GFX10+

radv/llvm,aco: always split typed vertex buffer loads on GFX6 and GFX10+

To avoid any alignment issues that triggers memory violations and
eventually a GPU. This can happen if the stride (static or dynamic)
is unaligned and also if the VBO offset is aligned to scalar
(eg. stride is 8 and VBO offset is 2 for R16G16B16A16_SNORM).

The AMD Windows driver also always splits typed vertex fetches.

fossils-db (Sienna Cichlid):
Totals from 56508 (40.54% of 139391) affected shaders:
SGPRs: 2643545 -> 2664516 (+0.79%); split: -0.19%, +0.98%
VGPRs: 2007472 -> 1995408 (-0.60%); split: -0.74%, +0.13%
CodeSize: 70596372 -> 73913312 (+4.70%); split: -0.00%, +4.70%
MaxWaves: 772653 -> 774916 (+0.29%); split: +0.37%, -0.08%
Instrs: 14074162 -> 14567072 (+3.50%); split: -0.00%, +3.51%
Cycles: 69281276 -> 71253252 (+2.85%); split: -0.00%, +2.85%
VMEM: 22047039 -> 25554196 (+15.91%); split: +17.20%, -1.29%
SMEM: 4120370 -> 4360820 (+5.84%); split: +7.41%, -1.58%
VClause: 416913 -> 438361 (+5.14%); split: -1.86%, +7.01%
SClause: 536739 -> 542637 (+1.10%); split: -0.33%, +1.43%
Copies: 977194 -> 970015 (-0.73%); split: -2.43%, +1.69%
Branches: 241205 -> 241193 (-0.00%); split: -0.06%, +0.06%
PreVGPRs: 1505645 -> 1505379 (-0.02%)

This fixes GPU hangs with bin/draw-vertices from Piglit on GFX10+
with Zink.

Cc: mesa-stable
Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8363>