Reduce unnecessary stack consuming of libpcap

Because the `filter_pcap_*` subprogs use its own stack memory, it is
unnecessary to reserved 80B stack memory.

Therefore, `filter_pcap_*` subprogs can use the whole stack memory.

Signed-off-by: Leon Hwang <[email protected]>

Author: Asphaltt

internal/libpcap/compile.go

@@ -28,7 +28,7 @@ const (
 type StackOffset int
 
 const (
-	BpfReadKernelOffset StackOffset = -8*(iota+1) - 80
+	BpfReadKernelOffset StackOffset = -8 * (iota + 1)
 	R1Offset
 	R2Offset
 	R3Offset