cxgbe: fix build with icc

cxgbe: fix build with icc

When compiling the cxgbe driver with icc, multiple errors about using
enums as integers appear across a number of files, including in the base
code and in the DPDK-specific driver code.

.../drivers/net/cxgbe/cxgbe_main.c(386): error #188: enumerated type mixed
with another type
                        t4_get_port_type_description(pi->port_type));
                                                     ^
For the errors in the base driver code we use the CFLAGS_BASE_DRIVER
approach used by other drivers to disable warnings.

For errors in the DPDK-specific code, typecasts are used to fix the
errors in the code itself.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>