ide_ioreg_t is deprecated and hasn't been used by IDE driver for some time.
Use unsigned long directly on alpha, arm26, arm, mips, parisc, ppc64 and sh.

asm-ia64/ide.h (ide_ioreg_t is unsigned short) and asm-m68knommu/ide.h
(broken - ide_ioreg_t is not defined) are the only users of ide_ioreg_t left.