arc: get rid of private asm/unaligned.h

arc: get rid of private asm/unaligned.h

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

Unlike the parisc case, here we have an extra twist - asm/mmu.h
has an implicit dependency on struct pt_regs, and in some users
that used to be satisfied by include of asm/ptrace.h from
asm/unaligned.h (note that asm/mmu.h itself did _not_ pull asm/unaligned.h
- it relied upon the users having pulled asm/unaligned.h before asm/mmu.h
got there).

Seeing that asm/mmu.h only wants struct pt_regs * arguments in
an extern, just pre-declare it there - less brittle that way.

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

What's more, we can move asm-generic/unaligned.h to linux/unaligned.h
and switch includes of <asm/unaligned.h> to <linux/unaligned.h>; that's
better off as an auto-generated commit, though, to be done by Linus
at -rc1 time next cycle.

Acked-by: Vineet Gupta <[email protected]>
Signed-off-by: Al Viro <[email protected]>