metrics: use golang.org/x/sys/unix to support Solaris (#22584)

Fixes #11113
Co-authored-by: rene <41963722+renaynay@users.noreply.github.com>

metrics/cpu_syscall.go

@@ -19,7 +19,7 @@
 package metrics
 
 import (
-	"syscall"
+	syscall "golang.org/x/sys/unix"
 
 	"github.com/ethereum/go-ethereum/log"
 )