drm/amd/display: Check clock table return

During the load processes for Renoir, our display code needs to retrieve
the SMU clock and voltage table, however, this operation can fail which
means that we have to check this scenario. Currently, we are not
handling this case properly and as a result, we have seen the following
dmesg log during the boot:

RIP: 0010:rn_clk_mgr_construct+0x129/0x3d0 [amdgpu]
...
Call Trace:
 dc_clk_mgr_create+0x16a/0x1b0 [amdgpu]
 dc_create+0x231/0x760 [amdgpu]

This commit fixes this issue by checking the return status retrieved
from the clock table before try to populate any bandwidth.

Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>