Add a platform prefix for function name in order to make more readable,
and move it into ath79.h
Signed-off-by: Wills Wang <wills.wang@live.com>
Acked-by: Marek Vasut <marex@denx.de>
GCC 5.3 report a warning: 'upper' and 'lower' may be used
uninitialized in this function [-Wmaybe-uninitialized].
Compiler might need explicit initializer.
Signed-off-by: Wills Wang <wills.wang@live.com>