ac: remove LLVM 4.0 workaround

This was added to fix https://bugs.freedesktop.org/show_bug.cgi?id=97988 but
has been fixed in LLVM since.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15559>

src/amd/llvm/ac_llvm_util.c

@@ -53,16 +53,9 @@ static void ac_init_llvm_target(void)
    /* For ACO disassembly. */
    LLVMInitializeAMDGPUDisassembler();
 
-   /* Workaround for bug in llvm 4.0 that causes image intrinsics
-    * to disappear.
-    * https://reviews.llvm.org/D26348
-    *
-    * "mesa" is the prefix for error messages.
-    *
-    */
    const char *argv[] = {
+      /* error messages prefix */
       "mesa",
-      "-simplifycfg-sink-common=false",
       "-amdgpu-atomic-optimizations=true",
 #if LLVM_VERSION_MAJOR == 11
       /* This fixes variable indexing on LLVM 11. It also breaks atomic.cmpswap on LLVM >= 12. */