mfd: tmio: Move register macros to tmio_core.c

These registers are only used in drivers/mfd/tmio_core.c

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>