[llvm] [AMDGPU] Fix v_dot2_f16_f16/v_dot2_bf16_bf16 operands (PR #82423)

[Shilei Tian via llvm-commits]

================
@@ -1833,6 +1839,12 @@
 # GFX11: v_dot2_f16_f16 v255, -|0xfe0b|, -|vcc_hi|, null op_sel:[0,0,0,1] ; encoding: [0xff,0x43,0x66,0xd6,0xff,0xd6,0xf0,0x61,0x0b,0xfe,0x00,0x00]
 0xff,0x43,0x66,0xd6,0xff,0xd6,0xf0,0x61,0x0b,0xfe,0x00,0x00
 
+# GFX11: v_dot2_f16_f16 v2, v0, 0x20004000, v2 ; encoding: [0x02,0x00,0x66,0xd6,0x00,0xff,0x09,0x04,0x00,0x40,0x00,0x20]
+0x02,0x00,0x66,0xd6,0x00,0xff,0x09,0x04,0x00,0x40,0x00,0x20
+
+# GFX11: v_dot2_f16_f16 v2, 0x20004000, v0, v2 ; encoding: [0x02,0x00,0x66,0xd6,0xff,0x00,0x0a,0x04,0x00,0x40,0x00,0x20]
+0x02,0x00,0x66,0xd6,0xff,0x00,0x0a,0x04,0x00,0x40,0x00,0x20
----------------
shiltian wrote:

How will it look like if `0x3f803f80` which represents `<bfloat 1.0, bfloat 1.0>`?

https://github.com/llvm/llvm-project/pull/82423