perf report: Allow user to specify path to kallsyms file

This is useful for analyzing a perf data file on a different system than
the one data was collected on and still include symbols from loaded
kernel modules in the output.

Commiter note: Updated the man page accordingly.

LKML-Reference: <1291775986-16475-1-git-send-email-daahern@cisco.com>
Signed-off-by: David Ahern <daahern@cisco.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 038f220..12defbe 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -72,6 +72,7 @@
 			show_cpu_utilization,
 			initialized;
 	const char	*vmlinux_name,
+			*kallsyms_name,
 			*source_prefix,
 			*field_sep;
 	const char	*default_guest_vmlinux_name,