virtio: fix newline under debug mode

virtio: fix newline under debug mode

Issue: output of appliations and debug info of DPDK may be mixed up
in same line when enabling below debug options of virtio:
CONFIG_RTE_LIBRTE_VIRTIO_DEBUG_INIT
CONFIG_RTE_LIBRTE_VIRTIO_DEBUG_TX
CONFIG_RTE_LIBRTE_VIRTIO_DEBUG_DRIVER

This patch adds "\n" in the tail of definitions like PMD_RX_LOG,
PMD_TX_LOG, and PMD_DRV_LOG, and removes some "\n" when using these
macros.

Fixes: c1f86306a026 ("virtio: add new driver")

Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>