dpaa2-switch: add bounds check for if_id in IRQ handler

dpaa2-switch: add bounds check for if_id in IRQ handler

The IRQ handler extracts if_id from the upper 16 bits of the hardware
status register and uses it to index into ethsw->ports[] without
validation. Since if_id can be any 16-bit value (0-65535) but the ports
array is only allocated with sw_attr.num_ifs elements, this can lead to
an out-of-bounds read potentially.

Add a bounds check before accessing the array, consistent with the
existing validation in dpaa2_switch_rx().

Reported-by: Yuhao Jiang <danisjiang@gmail.com>
Reported-by: Junrui Luo <moonafterrain@outlook.com>
Fixes: 24ab724f8a46 ("dpaa2-switch: use the port index in the IRQ handler")
Signed-off-by: Junrui Luo <moonafterrain@outlook.com>
Link: https://patch.msgid.link/SYBPR01MB7881D420AB43FF1A227B84AFAF91A@SYBPR01MB7881.ausprd01.prod.outlook.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>