Revert "aco: only emit waitcnt on loop continues if we there was some load or export"

Revert "aco: only emit waitcnt on loop continues if we there was some load or export"

We don't properly pass on ctx.lgkm_cnt/ctx.barrier_imm/etc, so this
waitcnt was necessary for barriers and correctly waiting for SMEM before
s_dcache_wb on GFX10.

Totals from affected shaders:
SGPRS: 33200 -> 33200 (0.00 %)
VGPRS: 31376 -> 31376 (0.00 %)
Spilled SGPRs: 0 -> 0 (0.00 %)
Spilled VGPRs: 0 -> 0 (0.00 %)
Private memory VGPRs: 0 -> 0 (0.00 %)
Scratch size: 0 -> 0 (0.00 %) dwords per thread
Code Size: 2431804 -> 2433956 (0.09 %) bytes
LDS: 316 -> 316 (0.00 %) blocks
Max Waves: 1609 -> 1609 (0.00 %)

This reverts commit 2c050b49b3d776f054f1265d5523cabb61f22fc3.

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>