parisc/unwind: call callback with toplevel address

[Naresh Kamboju]

Following build errors noticed while building Linux next 20211001
with gcc-11 for parisc architecture.

arch/parisc/kernel/stacktrace.c: In function 'dump_trace':
arch/parisc/kernel/stacktrace.c:20:13: error: 'regs' undeclared (first
use in this function)
   20 |         if (regs)
      |             ^~~~
arch/parisc/kernel/stacktrace.c:20:13: note: each undeclared
identifier is reported only once for each function it appears in
arch/parisc/kernel/stacktrace.c:21:22: error: implicit declaration of
function 'fn' [-Werror=implicit-function-declaration]
   21 |                 if (!fn(cookie, regs->iaoq[0]))
      |                      ^~
arch/parisc/kernel/stacktrace.c:21:25: error: 'cookie' undeclared
(first use in this function)
   21 |                 if (!fn(cookie, regs->iaoq[0]))
      |                         ^~~~~~
cc1: some warnings being treated as errors
make[3]: *** [scripts/Makefile.build:288:
arch/parisc/kernel/stacktrace.o] Error 1

Build config:
https://builds.tuxbuild.com/1ytbtyEg5SDSQgS2Oj9RsCM4ZmS/config

Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>

meta data:
-----------
    git_repo: https://gitlab.com/Linaro/lkft/mirrors/next/linux-next
    git_sha: a25006a77348ba06c7bc96520d331cd9dd370715
    git_short_log: a25006a77348 (\"Add linux-next specific files for 20211001\")
    kconfig:  defconfig
    kernel_version: 5.15.0-rc3
    target_arch: parisc
    toolchain: gcc-11

steps to reproduce:
https://builds.tuxbuild.com/1ytbtyEg5SDSQgS2Oj9RsCM4ZmS/tuxmake_reproducer.sh

--
Linaro LKFT
https://lkft.linaro.org