IB/rxe: Remove unnecessary enum values

Clang warns when an emumerated type is implicitly converted to another.

drivers/infiniband/sw/rxe/rxe.c:106:27: warning: implicit conversion
from enumeration type 'enum rxe_device_param' to different enumeration
type 'enum ib_atomic_cap' [-Wenum-conversion]
        rxe->attr.atomic_cap                    = RXE_ATOMIC_CAP;
                                                ~ ^~~~~~~~~~~~~~
drivers/infiniband/sw/rxe/rxe.c:131:22: warning: implicit conversion
from enumeration type 'enum rxe_port_param' to different enumeration
type 'enum ib_port_state' [-Wenum-conversion]
        port->attr.state                = RXE_PORT_STATE;
                                        ~ ^~~~~~~~~~~~~~
drivers/infiniband/sw/rxe/rxe.c:132:24: warning: implicit conversion
from enumeration type 'enum rxe_port_param' to different enumeration
type 'enum ib_mtu' [-Wenum-conversion]
        port->attr.max_mtu              = RXE_PORT_MAX_MTU;
                                        ~ ^~~~~~~~~~~~~~~~
drivers/infiniband/sw/rxe/rxe.c:133:27: warning: implicit conversion
from enumeration type 'enum rxe_port_param' to different enumeration
type 'enum ib_mtu' [-Wenum-conversion]
        port->attr.active_mtu           = RXE_PORT_ACTIVE_MTU;
                                        ~ ^~~~~~~~~~~~~~~~~~~
drivers/infiniband/sw/rxe/rxe.c:151:24: warning: implicit conversion
from enumeration type 'enum rxe_port_param' to different enumeration
type 'enum ib_mtu' [-Wenum-conversion]
                                ib_mtu_enum_to_int(RXE_PORT_ACTIVE_MTU);
                                ~~~~~~~~~~~~~~~~~~ ^~~~~~~~~~~~~~~~~~~
5 warnings generated.

Use the appropriate values from the expected enumerated type so no
conversion needs to happen then remove the unneeded definitions.

Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>