aco: consider non-hazard writes in handle_raw_hazard_internal

aco: consider non-hazard writes in handle_raw_hazard_internal

I think this helps GFX6 in particular because code like this is common:
s_add_i32       s4, 0x60, s3
s_mov_b32       s5, 0
s_load_dwordx4  s[4:7], s[4:5], 0x0
s_buffer_load_dword s4, s[4:7], 0xcc

pipeline-db (Tahiti):
Totals from affected shaders:
SGPRS: 1923878 -> 1923878 (0.00 %)
VGPRS: 1528964 -> 1528964 (0.00 %)
Spilled SGPRs: 476 -> 476 (0.00 %)
Spilled VGPRs: 0 -> 0 (0.00 %)
Scratch size: 0 -> 0 (0.00 %) dwords per thread
Code Size: 88723604 -> 88528880 (-0.22 %) bytes
LDS: 241 -> 241 (0.00 %) blocks
Max Waves: 145402 -> 145402 (0.00 %)

pipeline-db (Polaris):
Totals from affected shaders:
SGPRS: 428128 -> 428128 (0.00 %)
VGPRS: 353092 -> 353092 (0.00 %)
Spilled SGPRs: 119251 -> 119251 (0.00 %)
Spilled VGPRs: 0 -> 0 (0.00 %)
Scratch size: 0 -> 0 (0.00 %) dwords per thread
Code Size: 57580468 -> 57563964 (-0.03 %) bytes
LDS: 0 -> 0 (0.00 %) blocks
Max Waves: 11631 -> 11631 (0.00 %)

piepline-db (Vega):
Totals from affected shaders:
SGPRS: 425016 -> 425016 (0.00 %)
VGPRS: 349588 -> 349588 (0.00 %)
Spilled SGPRs: 117835 -> 117835 (0.00 %)
Spilled VGPRs: 0 -> 0 (0.00 %)
Scratch size: 0 -> 0 (0.00 %) dwords per thread
Code Size: 54890792 -> 54874432 (-0.03 %) bytes
LDS: 0 -> 0 (0.00 %) blocks
Max Waves: 54 -> 54 (0.00 %)

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4004>