CVE-2026-74320: fbdev: sm501fb: Fix buffer errors in OF binding code

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

fbdev: sm501fb: Fix buffer errors in OF binding code

The code that gets the frame buffer mode from OF has 'use after free', 'buffer overrun' and memory leaks.

info->ediddata isn't free if the probe functions fail or if pd->defmode is set.

If both the CRT and PANEL are enabled info->ediddata is used after being freed and is freed twice.

The string returned by ofgetproperty(np, "mode", &len) is just written over either the static "640x480-16@60" or the module parameter string without any regard for the length (which is most likely longer).

Use kstrump() for the OF mode and free everything before freeing 'info.