riscv: io: Update __io_[p]ar() macros to take an argument
The definitions of the __io_[p]ar() macros in asm-generic/io.h take the
value returned by the preceding I/O read as an argument so that
architectures can use this to create order with a subsequent delayX()
routine using a dependency.
Update the riscv barrier definitions to match, although the argument
is currently unused.