raid6: riscv: Clean up unused header file inclusion

raid6: riscv: Clean up unused header file inclusion

These two C files don't reference things defined in simd.h or types.h
so remove these redundant #inclusions.

Fixes: 6093faaf9593 ("raid6: Add RISC-V SIMD syndrome and recovery calculations")
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Chunyan Zhang <zhangchunyan@iscas.ac.cn>
Reviewed-by: Nutty Liu <liujingqi@lanxincomputing.com>
Link: https://lore.kernel.org/r/20250718072711.3865118-2-zhangchunyan@iscas.ac.cn
Signed-off-by: Paul Walmsley <pjw@kernel.org>