x86/stacktrace: update kconfig help text for reliable unwinders

x86/stacktrace: update kconfig help text for reliable unwinders

commit 6415b38bae26 ("x86/stacktrace: Enable HAVE_RELIABLE_STACKTRACE
for the ORC unwinder") added the ORC unwinder as a "reliable" unwinder.
Update the help text to reflect that change: the frame pointer unwinder
is no longer the only one that can provide HAVE_RELIABLE_STACKTRACE.

Link: http://lkml.kernel.org/r/20191107032958.14034-1-joe.lawrence@redhat.com
To: linux-kernel@vger.kernel.org
To: live-patching@vger.kernel.org
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>