hw/gpio/imx_gpio: Fix interpretation of GDIR polarity

hw/gpio/imx_gpio: Fix interpretation of GDIR polarity

According to the i.MX 8M Plus reference manual, a GPIO pin is
configured as an output when the corresponding bit in the GDIR
register is set.  The function imx_gpio_set_int_line() is intended to
be a no-op if the pin is configured as an output, returning early in
such cases.  However, it inverts the condition.  Fix this by
returning early when the bit is set.

cc: qemu-stable@nongnu.org
Fixes: f44272809779 ("i.MX: Add GPIO device")
Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Message-id: 20250501183445.2389-4-shentey@gmail.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
(cherry picked from commit eba837a31b9579e30cc6d7ecb4b5c2662a6ffaba)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>