staging: lttng: Update max symbol length to 256

The user-space tracer, along with the control tools, now support longer
event name strings (up to 256 chars, including \0).
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/lttng/ltt-debugfs-abi.h

@@ -13,7 +13,7 @@
 
 #include <linux/fs.h>
 
-#define LTTNG_SYM_NAME_LEN	128
+#define LTTNG_SYM_NAME_LEN	256
 
 enum lttng_kernel_instrumentation {
 	LTTNG_KERNEL_TRACEPOINT	= 0,