hash: fix build on IBM POWER and ARM
hash: fix build on IBM POWER and ARM

This patch fixes the compile errors caused by lacking of "size_t"
definition in rte_hash.h.
The compile error exists on IBM POWER and ARM.

The errors are like:
In file included from app/test/test_hash_scaling.c:35:0:
rte_hash.h:70:70: error: unknown type name ‘size_t’

Fixes: 95da2f8e9c61 ("hash: customize compare function")

Signed-off-by: Chao Zhu <fb95c043d5fa3fcf28eb07d8ee8ac9e1289ed03b@linux.vnet.ibm.com>
Acked-by: Jerin Jacob <5bca7d2a432bc0f5422b70b2701a4e4fa32edd00@caviumnetworks.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk