drm/vc4: fix krealloc() memory leak

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

drm/vc4: platformgetirqbyname() returns an int

platformgetirqbyname() will return a negative value if an error happens, so it should be checked and not just passed directly into devmrequestthreadedirq() hoping all will be ok.

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

drm/vc4: Fix memory leak of BO array in hang state

The hang state's BO array is allocated separately with kzalloc() in vc4savehangstate() but never freed in vc4freehangstate(). Add the missing kfree() for the BO array before freeing the hang state struct.

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

drm/vc4: Fix a memory leak in hang state error path

When vc4savehangstate() encounters an early return condition, it returns without freeing the previously allocated kernelstate, leaking memory.

Add the missing kfree() calls by consolidating the early return paths into a single place.