bnxt_en: fix clear flags in ethtool reset handling

Clear flags when reset command processed successfully for components
specified.

Fixes: 6502ad59 ("bnxt_en: Add ETH_RESET_AP support")
Signed-off-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>