amdgpu: add navi12 firmware from 20.30

From internal git commit:
889d8cb458bee9418dc8f92c45fe4850dc48b5b4
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Josh Boyer <jwboyer@kernel.org>

WHENCE

@@ -2378,6 +2378,21 @@ File: amdgpu/navi14_smc.bin
 File: amdgpu/navi14_sos.bin
 File: amdgpu/navi14_vcn.bin
 File: amdgpu/navi14_ta.bin
+File: amdgpu/navi12_asd.bin
+File: amdgpu/navi12_ce.bin
+File: amdgpu/navi12_dmcu.bin
+File: amdgpu/navi12_gpu_info.bin
+File: amdgpu/navi12_me.bin
+File: amdgpu/navi12_mec.bin
+File: amdgpu/navi12_mec2.bin
+File: amdgpu/navi12_pfp.bin
+File: amdgpu/navi12_rlc.bin
+File: amdgpu/navi12_sdma.bin
+File: amdgpu/navi12_sdma1.bin
+File: amdgpu/navi12_smc.bin
+File: amdgpu/navi12_sos.bin
+File: amdgpu/navi12_vcn.bin
+File: amdgpu/navi12_ta.bin
 File: amdgpu/renoir_asd.bin
 File: amdgpu/renoir_ce.bin
 File: amdgpu/renoir_gpu_info.bin