[AMDGPU][NFC] Docs - remove duplicates (#81465)

Author: mariusz-sikora-at-amd

llvm/docs/AMDGPUUsage.rst

@@ -1857,8 +1857,6 @@ The AMDGPU backend uses the following ELF header:
      ``EF_AMDGPU_MACH_AMDGCN_GFX942``           0x04c      ``gfx942``
      *reserved*                                 0x04d      Reserved.
      ``EF_AMDGPU_MACH_AMDGCN_GFX1201``          0x04e      ``gfx1201``
-     ``EF_AMDGPU_MACH_AMDGCN_GFX1201``          0x04e      ``gfx1201``
-     ``EF_AMDGPU_MACH_AMDGCN_GFX1201``          0x04e      ``gfx1201``
      *reserved*                                 0x04f      Reserved.
      *reserved*                                 0x050      Reserved.
      ``EF_AMDGPU_MACH_AMDGCN_GFX9_GENERIC``     0x051      ``gfx9-generic``