Add IRQ info to porting guide

Add it to the list of OS primitives, though it's platform, but it helps
in porting. Also, add details about nature of interrupt.

Signed-off-by: Chaitanya Tata <Chaitanya.Tata@nordicsemi.no>

Author: krish2718

nrf70_bm_lib/docs/source/nrf70_bm_porting_guide.rst

@@ -19,6 +19,10 @@ The reference implementation of the BM Driver for the Zephyr RTOS uses build-tim
     - Description
     - OS agnostic layer API
     - Reference Zephyr API
+  * - IRQ
+    - Used to manage the interrupts from the nRF70 Series device.
+    - nrf_wifi_osal_bus_qspi_dev_intr_reg()/nrf_wifi_osal_bus_qspi_dev_intr_unreg()
+    - gpio_add_callback()/gpio_remove_callback()
   * - Tasklet
     - Used to process offloaded tasks from the nRF70 ISR context  (typically events coming from the nRF70 Series device)
     - tasklet_schedule()
@@ -49,6 +53,10 @@ The reference implementation of the BM Driver for the Zephyr RTOS uses build-tim
 
    The synchronization primitives used in the latest reference implementation have been updated to use Zephyr spinlocks instead of semaphores.
 
+.. note ::
+
+   The IRQ for nRF70 Series is configued as a GPIO pin, and is Edge triggered i.e., interrupt to be triggered on pin state change to logical level 1.
+
 * *Driver model*: The reference implementation uses the Zephyr driver model to manage the nRF70 Series device.
 
     .. list-table:: Driver model porting guidelines