powerpc: types: use <asm-generic/int-*.h> for the powerpc architecture

This modifies <asm-powerpc/types.h> to use the <asm-generic/int-*.h>
generic include files.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Anton Blanchard <anton@samba.org>