scsi: ibmvscsi: Use GFP_KERNEL with dma_alloc_coherent() in initialize_event_pool()

scsi: ibmvscsi: Use GFP_KERNEL with dma_alloc_coherent() in initialize_event_pool()

During driver probe we allocate a dma region for our event pool.
Currently, zero is passed for the gfp_flags parameter. Driver probe
callbacks are run in process context and we hold no locks so we can sleep
here if necessary.

Fix by passing GFP_KERNEL explicitly to dma_alloc_coherent().

Link: https://lore.kernel.org/r/1547089149-20577-1-git-send-email-tyreld@linux.vnet.ibm.com
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>