drm/amd: Add missing definitions for `SMU_MAX_LEVELS_VDDGFX`

It is reported that on a Topaz dGPU the kernel emits:
amdgpu: can't get the mac of 5

This is because there is no definition for max levels of VDDGFX
declared for SMU71 or SMU7. The correct definition is VDDC so
use this.

Link: https://gitlab.freedesktop.org/drm/amd/-/issues/3049
Reviewed-by: Alex Deucher <[e-mail]>
Signed-off-by: Mario Limonciello <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/pm/powerplay/smumgr/ci_smumgr.c

···
 	case SMU_MAX_ENTRIES_SMIO:
 		return SMU7_MAX_ENTRIES_SMIO;
 	case SMU_MAX_LEVELS_VDDC:
+	case SMU_MAX_LEVELS_VDDGFX:
 		return SMU7_MAX_LEVELS_VDDC;
 	case SMU_MAX_LEVELS_VDDCI:
 		return SMU7_MAX_LEVELS_VDDCI;

drivers/gpu/drm/amd/pm/powerplay/smumgr/iceland_smumgr.c

···
 	case SMU_MAX_ENTRIES_SMIO:
 		return SMU71_MAX_ENTRIES_SMIO;
 	case SMU_MAX_LEVELS_VDDC:
+	case SMU_MAX_LEVELS_VDDGFX:
 		return SMU71_MAX_LEVELS_VDDC;
 	case SMU_MAX_LEVELS_VDDCI:
 		return SMU71_MAX_LEVELS_VDDCI;