KVM: selftests: riscv: Remove unneeded semicolon

Fix the following coccicheck warnings:

./tools/testing/selftests/kvm/lib/riscv/processor.c:353:3-4: Unneeded
semicolon.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Anup Patel <anup@brainfault.org>