arm64: Correctly report LR and SP for compat tasks

When a task crashes and we print debugging information, ensure that
compat tasks show the actual AArch32 LR and SP registers rather than the
AArch64 ones.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Git-commit: 6ca68e802612c87c31aa83d50c37ed0d88774a46
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Ian Maund <imaund@codeaurora.org>