[AMDGPU] Update s_get_barrier_state tests (llvm#75575)

Author: mariusz-sikora-at-amd

llvm/test/MC/AMDGPU/gfx12_asm_sop1.s

@@ -735,6 +735,15 @@ s_wakeup_barrier -1
 s_wakeup_barrier m0
 // GFX12: encoding: [0x7d,0x57,0x80,0xbe]
 
+s_get_barrier_state s3, -1
+// GFX12: encoding: [0xc1,0x50,0x83,0xbe]
+
+s_get_barrier_state s3, -2
+// GFX12: encoding: [0xc2,0x50,0x83,0xbe]
+
+s_get_barrier_state s3, m0
+// GFX12: encoding: [0x7d,0x50,0x83,0xbe]
+
 s_mov_b32 s0, s1
 // GFX12: encoding: [0x01,0x00,0x80,0xbe]