tty: serial: samsung: don't compare with zero an if (bitwise expression)

tty: serial: samsung: don't compare with zero an if (bitwise expression)

The bitwise AND with the fifo mask is used to check if the fifo is empty
or not, it doesn't care about the length, thus the comparison with zero
is implicit. Rely on the implicit comparison instead.

Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Link: https://lore.kernel.org/r/20240119104526.1221243-14-tudor.ambarus@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>