According to the Arm Architecture Reference Manual for A-profile
architecture you can't have one feature without having the other:
ID_AA64ZFR0_EL1.AES, bits [7:4]
> FEAT_SVE_AES implements the functionality identified by the value
0b0001.
> FEAT_SVE_PMULL128 implements the functionality identified by the value
0b0010.
> The permitted values are 0b0000 and 0b0010.
(The following was removed from the latest release of the specification,
but it appears to be a mistake that was not intended to relax the
architecture constraints. The discrepancy has been reported)
ID_AA64ISAR0_EL1.AES, bits [7:4]
> FEAT_AES implements the functionality identified by the value 0b0001.
> FEAT_PMULL implements the functionality identified by the value
0b0010.
> From Armv8, the permitted values are 0b0000 and 0b0010.
Approved in ACLE as https://github.com/ARM-software/acle/pull/352
a91ebcdd91