drivers: gpio: esp32: Properly convert interrupt triggering mode

Masks for level- and edge-triggering levels are 0, so the following
check will be always true:

    if ((flags & GPIO_INT_ACTIVE_LOW) == GPIO_INT_ACTIVE_LOW)

Invert the evaluation order, by checking the masks that are not 0
first.

Jira: ZEP-2557
Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>