xen: arm: update arm32 assembly primitives to Linux v3.16-rc6

xen: arm: update arm32 assembly primitives to Linux v3.16-rc6

bitops, cmpxchg, atomics: Import:
  c32ffce ARM: 7984/1: prefetch: add prefetchw invocations for barriered atomics
    Author: Will Deacon <will.deacon@arm.com>
    Signed-off-by: Will Deacon <will.deacon@arm.com>
    Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
atomics: In addition to the above import:
  db38ee8 ARM: 7983/1: atomics: implement a better __atomic_add_unless for v6+
    Author: Will Deacon <will.deacon@arm.com>
    Signed-off-by: Will Deacon <will.deacon@arm.com>
    Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
spinlocks: We have diverged from Linux, so no updates but note this in the README.

mem* and str*: Import:
  d98b90e ARM: 7990/1: asm: rename logical shift macros push pull into lspush lspull
    Author: Victor Kamensky <victor.kamensky@linaro.org>
    Suggested-by: Will Deacon <will.deacon@arm.com>
    Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org>
    Acked-by: Nicolas Pitre <nico@linaro.org>
    Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
  For some reason str* were mentioned under mem* in the README, fix.

libgcc: No changes, update baseline

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Julien Grall <julien.grall@linaro.org>