drm/amdgpu: off by one in amdgpu_device_attr_create_groups() error handling

This loop in the error handling code should start a "i - 1" and end at
"i == 0".  Currently it starts a "i" and ends at "i == 1".  The result
is that it removes one attribute that wasn't created yet, and leaks the
zeroeth attribute.

Fixes: 4e01847c ("drm/amdgpu: optimize amdgpu device attribute code")
Acked-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Kevin Wang <kevin1.wang@amd.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>