drm/exynos: vidi: fix to avoid directly dereferencing user pointer

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

drm/exynos: vidi: fix to avoid directly dereferencing user pointer

In vidi_connection_ioctl(), vidi->edid(user pointer) is directly

dereferenced in the kernel.

This allows arbitrary kernel memory access from the user space, so instead

of directly accessing the user pointer in the kernel, we should modify it

to copy edid to kernel memory using copy_from_user() and use it.