if_bnxt: drop redundant PCI disable in bnxt_fw_reset_close()

[sumit.saxena_broadcom.com]

Summary

bnxt_fw_reset_close() unconditionally called pci_disable_device()
after freeing the Rx IRQs, on every firmware reset, not just the
BNXT_STATE_FW_FATAL_COND path which already disables the device via
bnxt_fw_fatal_close(). BNXT_FW_RESET_STATE_ENABLE_DEV in
bnxt_fw_reset_task() already re-enables the device unconditionally,
so this wasn't leaving the device disabled, just adding an
unnecessary PCI disable/re-enable cycle around every non-fatal reset.