examples/l2fwd: fix build warning with system wide install

examples/l2fwd: fix build warning with system wide install

Caught when compiling this example with pkg-config:

 ## Building l2fwd
 ...
 main.c: In function ‘main’:
 main.c:716:3: warning: ‘rte_eth_dev_set_ptypes’ is deprecated: Symbol
 is not yet part of stable ABI [-Wdeprecated-declarations]
   716 |   ret = rte_eth_dev_set_ptypes(portid, RTE_PTYPE_UNKNOWN, NULL,
       |   ^~~
 In file included from main.c:38:
 ...build-x86-default/install-root/usr/local/include/rte_ethdev.h:2661:5:
 note: declared here
  2661 | int rte_eth_dev_set_ptypes(uint16_t port_id, uint32_t
 ptype_mask,
       |     ^~~~~~~~~~~~~~~~~~~~~~
 ln -sf l2fwd-shared build/l2fwd

Fixes: 9731df2e7554 ("examples/l2fwd: disable packet type parsing")

Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Ferruh Yigit <ferruh.yigit@intel.com>