ARM: 9406/1: Fix callchain_trace() return value

perf_callchain_store() return 0 on success, -1 otherwise, fix
callchain_trace() to return correct bool value. So walk_stackframe() can
have a chance to stop walking the stack ahead.

Fixes: 70ccc7c0

 ("ARM: 9258/1: stacktrace: Make stack walk callback consistent with generic code")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>