serial: sc16is7xx: remove obsolete loop in sc16is7xx_port_irq()

Commit 83444987 ("sc16is7xx: Fix for multi-channel stall") changed
sc16is7xx_port_irq() from looping multiple times when there was still
interrupts to serve. It simply changed the do {} while(1) loop to a
do {} while(0) loop, which makes the loop itself now obsolete.

Clean the code by removing this obsolete do {} while(0) loop.

Fixes: 83444987 ("sc16is7xx: Fix for multi-channel stall")
Cc:  <stable@vger.kernel.org>
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231221231823.2327894-5-hugo@hugovil.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>