riscv: remove unused labels in start.S

The labels nmi_vector, trap_vector and handle_reset in start.S are not
used for RISC-V. Remove them.

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
1 file changed