serial: sc16is7xx: drop redundant conversion to bool

The result of integer comparison already evaluates to bool. No need for
explicit conversion.

Signed-off-by: Xichao Zhao <zhao.xichao@vivo.com>
Link: https://lore.kernel.org/r/20250827024514.76149-1-zhao.xichao@vivo.com


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