bnxt_en: Fix compiler warnings when CONFIG_RFS_ACCEL is not defined.

bnxt_en: Fix compiler warnings when CONFIG_RFS_ACCEL is not defined.

Orabug: 25645429

CC [M]  drivers/net/ethernet/broadcom/bnxt/bnxt.o
drivers/net/ethernet/broadcom/bnxt/bnxt.c:4947:21: warning: ‘bnxt_get_max_func_rss_ctxs’ defined but not used [-Wunused-function]
 static unsigned int bnxt_get_max_func_rss_ctxs(struct bnxt *bp)
                     ^
  CC [M]  drivers/net/ethernet/broadcom/bnxt/bnxt.o
drivers/net/ethernet/broadcom/bnxt/bnxt.c:4956:21: warning: ‘bnxt_get_max_func_vnics’ defined but not used [-Wunused-function]
 static unsigned int bnxt_get_max_func_vnics(struct bnxt *bp)
                     ^

Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit b742995445fbac874f5fe19ce2afc76c7a6ac2cf)
Signed-off-by: Brian Maly <brian.maly@oracle.com>