[ARM] support tracing when using newer compilers

Since gcc 4.4 the name and calling convention for function profiling
on ARM changed.  With this patch both types are supported.

See http://sourceware.org/ml/libc-ports/2008-04/msg00009.html for some
details.

Lightly-Tested-by: Anand Gadiyar <gadiyar@ti.com>
Tested-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

arch/arm/kernel/armksyms.c

@@ -186,4 +186,5 @@ EXPORT_SYMBOL(_find_next_bit_be);
 
 #ifdef CONFIG_FUNCTION_TRACER
 EXPORT_SYMBOL(mcount);
+EXPORT_SYMBOL(__gnu_mcount_nc);
 #endif