bnxt_en: Fix wrong return value check in bnxt_close_nic()

bnxt_en: Fix wrong return value check in bnxt_close_nic()

The wait_event_interruptible_timeout() function returns 0
if the timeout elapsed, -ERESTARTSYS if it was interrupted
by a signal, and the remaining jiffies otherwise if the
condition evaluated to true before the timeout elapsed.

Driver should have checked for zero return value instead of
a positive value.

MChan: Print a warning for -ERESTARTSYS.  The close operation
will proceed anyway when wait_event_interruptible_timeout()
returns for any reason.  Since we do the close no matter what,
we should not return this error code to the caller.  Change
bnxt_close_nic() to a void function and remove all error
handling from some of the callers.

Fixes: c0c050c58d84 ("bnxt_en: New Broadcom ethernet driver.")
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Reviewed-by: Vikas Gupta <vikas.gupta@broadcom.com>
Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Signed-off-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Link: https://lore.kernel.org/r/20231208001658.14230-4-michael.chan@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>