[FMV] Remove features predres and ls64. (#382)

These cannot be detected by reading the ID_AA64ISAR1_EL1 register since
their corresponding bitfields are hidden according to the Linux Kernel
docs:


https://www.kernel.org/doc/html/latest/arch/arm64/cpu-feature-registers.html

Additionally the instructions that these features enable are unusable
from user space (Exception Level 0).

For SPECRES the Arm Architecture Reference Manual says:

In AArch64 state, EL0 access to the System instructions is controlled
by:
* When HCR_EL2.{E2H, TGE} is not {1, 1}, SCTLR_EL1.EnRCTX.
* When HCR_EL2.{E2H, TGE} == {1, 1}, SCTLR_EL2.EnRCTX.

For LS64 it says:

* SCTLR_EL1.EnALS, bit [56] : When FEAT_LS64 is implemented: When the
Effective value of HCR_EL2.{E2H, TGE} is not {1, 1}, traps execution of
an LD64B or ST64B instruction at EL0 to EL1.

* SCTLR_EL1.EnAS0, bit [55] : When FEAT_LS64_ACCDATA is implemented:
When the Effective value of HCR_EL2.{E2H, TGE} is not {1, 1}, traps
execution of an ST64BV0 instruction at EL0 to EL1.

* SCTLR_EL1.EnASR, bit [54] : When FEAT_LS64_V is implemented: When the
Effective value of HCR_EL2.{E2H, TGE} is not {1, 1}, traps execution of
an ST64BV instruction at EL0 to EL1.

main/acle.md

@@ -422,6 +422,7 @@ Armv8.4-A [[ARMARMv84]](#ARMARMv84). Support is added for the Dot Product intrin
 * Removed Function Multi Versioning features sve-bf16, sve-ebf16, and sve-i8mm.
 * Removed Function Multi Versioning features ebf16, memtag3, and rpres.
 * Removed Function Multi Versioning feature dgh.
+* Removed Function Multi Versioning features ls64 and predres.
 * Document Function Multi Versioning feature dependencies.
 * Clarify Function Multi Versioning feature dependency rule.
 * Simplified Function Multi Versioning version selection rules.
@@ -2866,10 +2867,8 @@ The following table lists the architectures feature mapping for AArch64
    | 430           | `FEAT_SME`               | sme           | ```ID_AA64PFR1_EL1.SME >= 0b0001```       |
    | 440           | `FEAT_MTE`, `FEAT_MTE2`  | memtag        | ```ID_AA64PFR1_EL1.MTE >= 0b0010```       |
    | 470           | `FEAT_SB`                | sb            | ```ID_AA64ISAR1_EL1.SB >= 0b0001```       |
-   | 480           | `FEAT_SPECRES`           | predres       | ```ID_AA64ISAR1_EL1.SPECRES >= 0b0001```  |
    | 490           | `FEAT_SSBS`, `FEAT_SSBS2`| ssbs          | ```ID_AA64PFR1_EL1.SSBS >= 0b0010```      |
    | 510           | `FEAT_BTI`               | bti           | ```ID_AA64PFR1_EL1.BT >= 0b0001```        |
-   | 520           | `FEAT_LS64`, `FEAT_LS64_V`, <br> `FEAT_LS64_ACCDATA` | ls64 | ```ID_AA64ISAR1_EL1.LS64 >= 0b0011``` |
    | 550           | `FEAT_WFxT`              | wfxt          | ```ID_AA64ISAR2_EL1.WFxT >= 0b0010```     |
    | 560           | `FEAT_SME_F64F64`        | sme-f64f64    | ```ID_AA64SMFR0_EL1.F64F64 == 0b1```      |
    | 570           | `FEAT_SME_I16I64`        | sme-i16i64    | ```ID_AA64SMFR0_EL1.I16I64 == 0b1111```   |