bus/fslmc: move VFIO DMA map into bus probe

bus/fslmc: move VFIO DMA map into bus probe

fslmc bus needs to map all allocated memory for VFIO before
device probe. This bus doesn't support hotplug, so at the time
of this call, all possible device that could be present, are
present. This will also be the place where we install VFIO
callback, although this change will come in the next patch.

Since rte_fslmc_vfio_dmamap() is now only called at bus probe,
there is no longer any need to check if DMA mappings have been
already done.

Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Tested-by: Santosh Shukla <santosh.shukla@caviumnetworks.com>
Tested-by: Hemant Agrawal <hemant.agrawal@nxp.com>
Tested-by: Gowrishankar Muthukrishnan <gowrishankar.m@linux.vnet.ibm.com>