eal: auto detect IOVA mode

eal: auto detect IOVA mode

iova autodetection depends on rte_bus_scan result. Result of bus scan will
have updated device_list and each device in that list has its '.kdev' state
updated. That kdrv state used to detect iova mapping mode for that device.

_device_parse() has dependency on rt_bus_scan so,
Below calls moved up in the eal initialization order:
	- eal_option_device_parse
	- rte_bus_scan

And based on the result of rte_bus_scan_iommu_class - select iova
mapping mode.

Signed-off-by: Santosh Shukla <santosh.shukla@caviumnetworks.com>
Signed-off-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>
Tested-by: Hemant Agrawal <hemant.agrawal@nxp.com>