This reverts commit 6ac9b61786.
This commit was required because at that time, ioread/iowrite
functions were sub-optimal on powerpc/32 compared to the
architecture specific in_/out_ IO accessors.
But there are now equivalent since
commit 894fa235eb ("powerpc: inline iomap accessors").
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Li Yang <leoyang.li@nxp.com>