riscv: import read/write_relaxed functions

This imports mmio functions from Linux's arch/riscv/include/asm/mmio.h
to use read/write[b|w|l|q]_relaxed functions.

Signed-off-by: Chanho Park <chanho61.park@samsung.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
1 file changed