The commit 3f70a6f5 ("x86: Add clr/setbits functions")
introduced the {read|write}_ macros to manipulate data.

Those macros are not used by any code in the u-boot project (despite the
io.h itself). Other architectures use io.h with {in|out}_* macros.

This commit brings some unification across u-boot supported architectures.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>