drm: Do not allow userspace to trigger kernel warnings in drm_gem_change_handle_ioctl()

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

drm: Do not allow userspace to trigger kernel warnings in drm_gem_change_handle_ioctl()

Since GEM bo handles are u32 in the uapi and the internal implementation
uses idr_alloc() which uses int ranges, passing a new handle larger than
INT_MAX trivially triggers a kernel warning:

idr_alloc():
...
if (WARN_ON_ONCE(start < 0))
return -EINVAL;
...

Fix it by rejecting new handles above INT_MAX and at the same time make
the end limit calculation more obvious by moving into int domain.