drm/amdgpu/discovery: parse hw_id_name for SDMA instance 2 and 3

Otherwise, hw_id_name string is NULL for SDMA 2 and 3 when dumping
ip version from VBIOS.
Signed-off-by: Guchun Chen <guchun.chen@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c

@@ -108,6 +108,8 @@ static const char *hw_id_names[HW_ID_MAX] = {
 	[HDP_HWID]		= "HDP",
 	[SDMA0_HWID]		= "SDMA0",
 	[SDMA1_HWID]		= "SDMA1",
+	[SDMA2_HWID]		= "SDMA2",
+	[SDMA3_HWID]		= "SDMA3",
 	[ISP_HWID]		= "ISP",
 	[DBGU_IO_HWID]		= "DBGU_IO",
 	[DF_HWID]		= "DF",