ethdev: fix ESP packet type description

[ upstream commit f647d53bdebc1a9273c01caad280aadc64d0487e ]

The correct protocol number for ESP (IP Encapsulating Security Payload)
packet type is 50. 51 is IPSec AH (Authentication Header).

Fixes: 1e84afd ("mbuf: add security crypto flags and fields")

Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com>
Reviewed-by: Morten Brørup <mb@smartsharesystems.com>

lib/mbuf/rte_mbuf_ptype.h

@@ -419,10 +419,10 @@ extern "C" {
  *
  * Packet format:
  * <'ether type'=0x0800
- * | 'version'=4, 'protocol'=51>
+ * | 'version'=4, 'protocol'=50>
  * or,
  * <'ether type'=0x86DD
- * | 'version'=6, 'next header'=51>
+ * | 'version'=6, 'next header'=50>
  */
 #define RTE_PTYPE_TUNNEL_ESP                0x00009000
 /**