Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index c075f4e..ee24fa1 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1268,7 +1268,7 @@
 		p->flags = 0L;
 
 		/*
-		 * Do the initial record convertion from mcount jump
+		 * Do the initial record conversion from mcount jump
 		 * to the NOP instructions.
 		 */
 		if (!ftrace_code_disable(mod, p)) {
@@ -3425,7 +3425,7 @@
 	atomic_set(&t->tracing_graph_pause, 0);
 	atomic_set(&t->trace_overrun, 0);
 	t->ftrace_timestamp = 0;
-	/* make curr_ret_stack visable before we add the ret_stack */
+	/* make curr_ret_stack visible before we add the ret_stack */
 	smp_wmb();
 	t->ret_stack = ret_stack;
 }