drm/amd/display: Fix USB4 hot plug crash issue

[Why]
Notify data from outbox corrupt, the notify type should be 2 (HPD) instead of 0
(No data). We copied the address instead of the value. The memory might be
freed in the end of outbox IRQ

[How]
We should allocate the memory of notify and copy the whole content from outbox to
hpd handle function

Fixes: 88f52b1f ("drm/amd/display: Support for SET_CONFIG processing with DMUB")
Signed-off-by: Jude Shih <shenshih@amd.com>
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>