drm/amdgpu: rename the ip_dump to ip_dump_core

Rename the memory pointer from ip_dump to ip_dump_core
to make it specific to core registers and rest other
registers to be dumped in their respective memories.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sunil Khatri <sunil.khatri@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>