perf symbols: Remove incorrect open-coded container_of()

perf symbols: Remove incorrect open-coded container_of()

At least on ARM, padding is inserted between rb_node and sym in struct
symbol_name_rb_node, causing "((void *)sym) - sizeof(struct rb_node)" to
point inside rb_node rather than to the symbol_name_rb_node.  Fix this
by converting the code to use container_of().

Cc: Ian Munsie <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Ming Lei <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Tom Zanussi <[email protected]>
LKML-Reference: <20101123163106.GA25677@debian>
Signed-off-by: Rabin Vincent <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>