bnxt_en: Fix build error for kernesl without RTC-LIB

bnxt_en: Fix build error for kernesl without RTC-LIB

Orabug: 24567991

bnxt_hwrm_fw_set_time() now returns -EOPNOTSUPP when built for kernel
without RTC_LIB.  Setting the firmware time is not critical to the
successful completion of the firmware update process.

Signed-off-by: Rob Swindell <Rob.Swindell@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 878786d95e07ce2f5fb6e3cd8a6c2ed320339196)
Signed-off-by: Brian Maly <brian.maly@oracle.com>
Signed-off-by: Dhaval Giani <dhaval.giani@oracle.com>