fix: remove unsupported PREFETCHW instruction

Author: OrlovEvgeny

internal/prefetch/prefetch_amd64.go

@@ -28,9 +28,3 @@ func PrefetchT2(addr unsafe.Pointer)
 //
 //go:noescape
 func PrefetchNTA(addr unsafe.Pointer)
-
-// PrefetchW prefetches data for writing.
-// Brings cache line into exclusive state, useful before a write operation.
-//
-//go:noescape
-func PrefetchW(addr unsafe.Pointer)

internal/prefetch/prefetch_amd64.s

@@ -33,9 +33,4 @@ TEXT ·PrefetchNTA(SB), NOSPLIT, $0-8
     PREFETCHNTA (AX)
     RET
 
-// func PrefetchW(addr unsafe.Pointer)
-// Prefetch for write (brings cache line into exclusive state)
-TEXT ·PrefetchW(SB), NOSPLIT, $0-8
-    MOVQ addr+0(FP), AX
-    PREFETCHW (AX)
-    RET
+

internal/prefetch/prefetch_other.go

@@ -15,6 +15,3 @@ func PrefetchT2(addr unsafe.Pointer) {}
 
 // PrefetchNTA is a no-op on non-amd64 platforms.
 func PrefetchNTA(addr unsafe.Pointer) {}
-
-// PrefetchW is a no-op on non-amd64 platforms.
-func PrefetchW(addr unsafe.Pointer) {}