riscv: s64ilp32: Validate harts by architecture name

When rv64ilp32 was introduced, the 32BIT would work with rv64,isa. So
use the architecture name instead of the ABI width name. This is an
addition to the commit: 069b0d51 ("RISC-V: validate riscv,isa at
boot, not during ISA string parsing").

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>