sisfb: remove duplicate function declarations

Remove duplicate register I/O function declarations by moving them into
a common header file.

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Thomas Winischhofer <thomas@winischhofer.net>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

diff --cc drivers/video/sis/init.h
Simple merge

diff --cc drivers/video/sis/init301.h
Simple merge

diff --cc drivers/video/sis/sis.h
Simple merge