rte_eth_dev_count is deprecated and use rte_eth_dev_count_avail instead.

Signed-off-by: Qingmin Liu <qingmin.liu@broadcom.com>

dpdk-iface-kmod: remove warning of ‘rte_eth_dev_count’ is deprecated.

- Use variable CROSS to specify toolchain prefix
- Use variable RTE_KERNELDIR to specify kernel build dir
  if RTE_KERNELDIR is not defined.

Signed-off-by: Qingmin Liu <qingmin.liu@broadcom.com>

- If ARCH is not defined, retrieve it from system.
- Only x86_64 adds -m64

Signed-off-by: Qingmin Liu <qingmin.liu@broadcom.com>

- If not it cannot find external lib

Signed-off-by: Qingmin Liu <qingmin.liu@broadcom.com>

- Verified at ARM64 Platform.
- For dependencies, introduce ext_lib to specify the dir.

Signed-off-by: Qingmin Liu <qingmin.liu@broadcom.com>

Cross-compile build support

…X ring size

In dpdk_module.c,TX/RX ring size is hard coded to 128, this prevent mTCP example
apps from running in VMware ESXi VM since VMXNET3 PMD default TX descriptor ring size
minimum value is 512. With this new config option, mTCP example app users can specify
the DPDK TX/RX descriptor ring size to fit in users environment.

    ab requires apr to be built with mTCP and DPDK library support
    the existing documents is missing steps to compile apr with mTCP

Add num_tx/num_rx config option to specify the DPDK driver TX/RX ring size

Renamed num_tx, num_rx to num_tx_desc, num_rx_desc respectively.
Replaced atoi() function with strtol().

Signed-off-by: Asim Jamshed <muhammad.jamshed@intel.com>