enic: fix pci_alloc_consistent argument

Fix build warning on i386 (32-bit) with 32-bit dma_addr_t:

drivers/net/enic/vnic_dev.c: In function 'vnic_dev_init_prov':
drivers/net/enic/vnic_dev.c:716: warning: passing argument 3 of 'pci_alloc_consistent' from incompatible pointer type
include/asm-generic/pci-dma-compat.h:16: note: expected 'dma_addr_t *' but argument is of type 'u64 *'

Now builds without warnings on i386 and on x86_64.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc:	Scott Feldman <scofeldm@cisco.com>
Cc:	Vasanthy Kolluri <vkolluri@cisco.com>
Cc:	Roopa Prabhu <roprabhu@cisco.com>
Acked-by: Scott Feldman <scofeldm@cisco.com>