cache: sifive: Fix -Wint-to-pointer-cast warning
The following warning is seen in cache-sifive-ccache.c in a 32-bit build:
warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
Fix by casting it with uintptr_t.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>