xtensa: fix KASAN report for show_stack

stable inclusion
from stable-v5.10.177
commit 08bfd05987df2756aaf7b2b8f014c4cdcc6bcb39
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I88YNP

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=08bfd05987df2756aaf7b2b8f014c4cdcc6bcb39



--------------------------------

commit 1d3b7a78 upstream.

show_stack dumps raw stack contents which may trigger an unnecessary
KASAN report. Fix it by copying stack contents to a temporary buffer
with __memcpy and then printing that buffer instead of passing stack
pointer directly to the print_hex_dump.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>