parisc: get rid of private asm/unaligned.h

Declarations local to arch/*/kernel/*.c are better off *not* in a public
header - arch/parisc/kernel/unaligned.h is just fine for those
bits.

With that done parisc asm/unaligned.h is reduced to include
of asm-generic/unaligned.h and can be removed - unaligned.h is in
mandatory-y in include/asm-generic/Kbuild.

Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>