arch: Simplify and correct style of VecReg types.
arch: Simplify and correct style of VecReg types.

Change-Id: Ib15d2e03c3e9cabcf56b316d5c57d2e892ad255d
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/41993
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