[backports-release-1.10] Remove bfloat16 condition accidentally backported

[imciner2]

This BFloat16 part was backported to 1.10 as part of #54471, but 1.10 doesn't actually have the BFloat16 support that this goes along with, and it has broken the build. So remove the condition.

cc @gbaraldi

[imciner2]

The errors are at least in tests now, so the build is fixed. Although, I think both failing tests are due to other changes in the backports branch. They are:

Error in testset intrinsics:
Error During Test at C:\buildkite-agent\builds\win2k22-amdci6-5\julialang\julia-release-1-dot-10\julia-99c9fed7fa\share\julia\test\intrinsics.jl:365
  Got exception outside of a @test
  Failed to parse LLVM assembly:
  <string>:1:8: error: expected type
  define ptr addrspace(1) @entry(ptr addrspace(1) %0) #0 {
         ^
  Stacktrace:
   [1] passthrough
     @ C:\buildkite-agent\builds\win2k22-amdci6-5\julialang\julia-release-1-dot-10\julia-99c9fed7fa\share\julia\test\intrinsics.jl:366 [inlined]
   [2] (::Main.Test36Main_intrinsics.var"#f#61"{Main.Test36Main_intrinsics.var"#passthrough#60"})(gws::Ptr{Nothing})
     @ Main.Test36Main_intrinsics C:\buildkite-agent\builds\win2k22-amdci6-5\julialang\julia-release-1-dot-10\julia-99c9fed7fa\share\julia\test\intrinsics.jl:374
   [3] macro expansion
     @ C:\buildkite-agent\builds\win2k22-amdci6-5\julialang\julia-release-1-dot-10\julia-99c9fed7fa\share\julia\test\intrinsics.jl:375 [inlined]
   [4] macro expansion
     @ C:\buildkite-agent\builds\win2k22-amdci6-5\julialang\julia-release-1-dot-10\julia-99c9fed7fa\share\julia\stdlib\v1.10\Test\src\Test.jl:1582 [inlined]
   [5] top-level scope
     @ C:\buildkite-agent\builds\win2k22-amdci6-5\julialang\julia-release-1-dot-10\julia-99c9fed7fa\share\julia\test\intrinsics.jl:366
Error in testset Unicode:
Test Failed at C:\buildkite-agent\builds\win2k22-amdci6-5\julialang\julia-release-1-dot-10\julia-99c9fed7fa\share\julia\stdlib\v1.10\Unicode\test\runtests.jl:288
  Expression: #= C:\buildkite-agent\builds\win2k22-amdci6-5\julialang\julia-release-1-dot-10\julia-99c9fed7fa\share\julia\stdlib\v1.10\Unicode\test\runtests.jl:288 =# @allocated(length(graphemes("äöüx"))) == 0
   Evaluated: 8 == 0

So I'd suggest merging this in and picking up on the test failures in the main backports PR.