bpf, doc: Change right arguments for JIT example code

The example code for the x86_64 JIT uses the wrong arguments when
calling function bar().

Signed-off-by: Mao Wenan <[e-mail]>
Signed-off-by: Daniel Borkmann <[e-mail]>
Link: https://lore.kernel.org/bpf/[e-mail]

Documentation/networking/filter.txt

···
     callq foo
     mov %rax,%r13
     mov %rbx,%rdi
-    mov $0x2,%esi
-    mov $0x3,%edx
-    mov $0x4,%ecx
-    mov $0x5,%r8d
+    mov $0x6,%esi
+    mov $0x7,%edx
+    mov $0x8,%ecx
+    mov $0x9,%r8d
     callq bar
     add %r13,%rax
     mov -0x228(%rbp),%rbx