dpaa2-switch: validate num_ifs to prevent out-of-bounds write

In the Linux kernel, the following vulnerability has been resolved:

dpaa2-switch: validate num_ifs to prevent out-of-bounds write

The driver obtains sw_attr.num_ifs from firmware via dpsw_get_attributes()

but never validates it against DPSW_MAX_IF (64). This value controls

iteration in dpaa2_switch_fdb_get_flood_cfg(), which writes port indices

into the fixed-size cfg->if_id[DPSW_MAX_IF] array. When firmware reports

num_ifs >= 64, the loop can write past the array bounds.

Add a bound check for num_ifs in dpaa2_switch_init().

dpaa2_switch_fdb_get_flood_cfg() appends the control interface (port

num_ifs) after all matched ports. When num_ifs == DPSW_MAX_IF and all

ports match the flood filter, the loop fills all 64 slots and the control

interface write overflows by one entry.

The check uses >= because num_ifs == DPSW_MAX_IF is also functionally

broken.

build_if_id_bitmap() silently drops any ID >= 64:

if (id[i] < DPSW_MAX_IF)

bmap[id[i] / 64] |= ...