stackleak: Rename stackleak_track_stack to __sanitizer_cov_stack_depth

The Clang stack depth tracking implementation has a fixed name for
the stack depth tracking callback, "__sanitizer_cov_stack_depth", so
rename the GCC plugin function to match since the plugin has no external
dependencies on naming.

Link: https://lore.kernel.org/r/20250717232519.2984886-2-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>

kernel/kstack_erase.c

@@ -156,7 +156,7 @@ asmlinkage void noinstr stackleak_erase_off_task_stack(void)
 	__stackleak_erase(false);
 }
 
-void __used __no_caller_saved_registers noinstr stackleak_track_stack(void)
+void __used __no_caller_saved_registers noinstr __sanitizer_cov_stack_depth(void)
 {
 	unsigned long sp = current_stack_pointer;
 
@@ -174,4 +174,4 @@ void __used __no_caller_saved_registers noinstr stackleak_track_stack(void)
 		current->lowest_stack = sp;
 	}
 }
-EXPORT_SYMBOL(stackleak_track_stack);
+EXPORT_SYMBOL(__sanitizer_cov_stack_depth);