ide: remove static prototypes from include/asm-mips/mach-au1x00/au1xxx_ide.h

This patch removes the static prototypes from the au1xxx_ide.h, some of
them were not even implemented. Also, they caused build breakage since
they differed from the functions actually implemented in
drivers/ide/mips/au1xxx-ide.c.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>