tracing: Fix typo in fpgraph.c

Fix typo "reservered" to "reserved".

Link: https://patch.msgid.link/20251121221835.28032-3-mhi@mailbox.org
Signed-off-by: Maurice Hieronymus <mhi@mailbox.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Author: sysheap

kernel/trace/fgraph.c

@@ -163,7 +163,7 @@ enum {
 #define RET_STACK(t, offset) ((struct ftrace_ret_stack *)(&(t)->ret_stack[offset]))
 
 /*
- * Each fgraph_ops has a reservered unsigned long at the end (top) of the
+ * Each fgraph_ops has a reserved unsigned long at the end (top) of the
  * ret_stack to store task specific state.
  */
 #define SHADOW_STACK_TASK_VARS(ret_stack) \