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.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>