[FMV][AArch64] Remove feature dgh since it can be used unconditionally.

The DGH instruction belongs to the hint space. It executes as NOP if
the corresponding feature is not present in hardware, so there's no
need for runtime dispatch.

main/acle.md

@@ -419,6 +419,7 @@ Armv8.4-A [[ARMARMv84]](#ARMARMv84). Support is added for the Dot Product intrin
 * Unified Function Multi Versioning features memtag and memtag2.
 * Unified Function Multi Versioning features aes and pmull.
 * Unified Function Multi Versioning features sve2-aes and sve2-pmull128.
+* Removed Function Multi Versioning feature dgh.
 * Fixed range of operand `o0` (too small) in AArch64 system register designations.
 * Fixed SVE2.1 quadword gather load/scatter store intrinsics.
 
@@ -2800,7 +2801,6 @@ The following table lists the architectures feature mapping for AArch64
    | 240           | `FEAT_LRCPC2`            | rcpc2         | ```ID_AA64ISAR1_EL1.LRCPC >= 0b0010```    |
    | 241           | `FEAT_LRCPC3`            | rcpc3         | ```ID_AA64ISAR1_EL1.LRCPC >= 0b0011```    |
    | 250           | `FEAT_FRINTTS`           | frintts       | ```ID_AA64ISAR1_EL1.FRINTTS >= 0b0001```  |
-   | 260           | `FEAT_DGH`               | dgh           | ```ID_AA64ISAR1_EL1.DGH >= 0b0001```      |
    | 270           | `FEAT_I8MM`              | i8mm          | ```ID_AA64ISAR1_EL1.I8MM >= 0b0001```     |
    | 280           | `FEAT_BF16`              | bf16          | ```ID_AA64ISAR1_EL1.BF16 >= 0b0001```     |
    | 290           | `FEAT_EBF16`             | ebf16         | ```ID_AA64ISAR1_EL1.BF16 >= 0b0010```     |