lvgl: nxp: pxp: Fix irq enablement for Zephyr

[0xFarahFl]

Description of the feature or fix

For Zephyr RTOS, irq is not correctly enabled and disabled. Fix it.

Checkpoints

• [x] Follow the styling guide
• [x] Run code-format.py from the scripts folder. astyle needs to be installed.
• [x] Update the documentation

[faxe1008]

Thanks for your submission 👍 . For the zephyr cloned modules generally we want to upstream changes and pull them in the next release. I will open a upstream LVGL PR containing your changes and link them in here.