arch-arm: mark ID_AA64ISAR1_EL1.JSCVT implemented
arch-arm: mark ID_AA64ISAR1_EL1.JSCVT implemented

The feature was implemented at: I1b24839daef775bbb1eb9da5f32c4bb3843e0b28

Change-Id: I0c0f55e55a1ca3ca6bf40206a989ef0bb353ee84
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/30934
Reviewed-by: Giacomo Travaglini <8eef13a4f970e2e9372c8d26ad0737b760f99c02@arm.com>
Maintainer: Giacomo Travaglini <8eef13a4f970e2e9372c8d26ad0737b760f99c02@arm.com>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>

gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5