Remove unused push packet payload byte function

src/packet.asm

@@ -2,24 +2,6 @@
 ; you can also push bytes into a packer buffer
 ; see packer.asm for that
 
-push_packet_payload_byte:
-    ; push_packet_payload_byte [rax]
-    ;  rax = (or al) is the byte as value to be pushed into the `udp_send_buf`
-    push rcx
-    push rdx
-
-    mov dword edx, [udp_payload_index]
-    lea rcx, [udp_send_buf + PACKET_HEADER_LEN + edx]
-    mov byte [rcx], al
-
-    mov rcx, [udp_payload_index]
-    inc rcx
-    mov [udp_payload_index], rcx
-
-    pop rdx
-    pop rcx
-    ret
-
 %macro packet_packer_reset 0
     mov dword [udp_payload_index], 0