[llvm] [GlobalISel][AArch64] Legalize G_FABS and G_FNEG for SVE (PR #114784)

[Thorsten Schütt via llvm-commits]

tschuett wrote:

End we up again at:
` defm FNEG_ZPmZ : sve_int_un_pred_arit_bitwise_fp<0b101, "fneg", AArch64fneg_mt>;`

https://github.com/llvm/llvm-project/pull/114784