[MC][Disassembler][AMDGPU] Remove unused check prefix

Author: RKSimon

llvm/test/MC/Disassembler/AMDGPU/vcmp-gfx10.txt

@@ -1,5 +1,5 @@
-# RUN: llvm-mc -arch=amdgcn -mcpu=gfx1010 -mattr=+wavefrontsize32,-wavefrontsize64 -disassemble -show-encoding < %s | FileCheck -check-prefixes=GFX10,W32 %s
-# RUN: llvm-mc -arch=amdgcn -mcpu=gfx1010 -mattr=-wavefrontsize32,+wavefrontsize64 -disassemble -show-encoding < %s | FileCheck -check-prefixes=GFX10,W64 %s
+# RUN: llvm-mc -arch=amdgcn -mcpu=gfx1010 -mattr=+wavefrontsize32,-wavefrontsize64 -disassemble -show-encoding < %s | FileCheck -check-prefix=W32 %s
+# RUN: llvm-mc -arch=amdgcn -mcpu=gfx1010 -mattr=-wavefrontsize32,+wavefrontsize64 -disassemble -show-encoding < %s | FileCheck -check-prefix=W64 %s
 
 # W32: v_cmp_class_f16_sdwa ttmp14, v1, v2 src0_sel:DWORD src1_sel:DWORD ; encoding: [0xf9,0x04,0x1e,0x7d,0x01,0xfa,0x06,0x06]
 # W64: v_cmp_class_f16_sdwa ttmp[14:15], v1, v2 src0_sel:DWORD src1_sel:DWORD ; encoding: [0xf9,0x04,0x1e,0x7d,0x01,0xfa,0x06,0x06]