Revert "drm/amd/amdgpu: Fix potential ioremap() memory leaks in amdgpu_device_init()"

This patch causes the following iounmap erorr and calltrace
iounmap: bad address 00000000d0b3631f

The original patch was unjustified because amdgpu_device_fini_sw() will
always cleanup the rmmio mapping.

This reverts commit eb4f1398

.

Signed-off-by: Ma Jun <Jun.Ma2@amd.com>
Suggested-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>