Use BIT() and GENMASK() for register field macros.  This will make
it easier to compare the macros with the register description in the
Denali User's Guide.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>