[PATCH] RAS: Avoid build errors when CONFIG_DEBUG_FS=n

[Yazen Ghannam]

A new helper was introduced for RAS modules to get be able to get the
RAS subsystem debugfs root directory. The helper is defined in debugfs.c
which is only built when CONFIG_DEBUG_FS=y.

However, it's possible that the modules would include debugfs support
for optional functionality. One current example is the fmpm module. In
this case, a build error will occur when CONFIG_RAS_FMPM is selected and
CONFIG_DEBUG_FS=n.

Add an inline helper function stub for the CONFIG_DEBUG_FS=n case.

Fixes: 9d2b6fa09d15 ("RAS: Export helper to get ras_debugfs_dir")
Reported-by: anthony s. knowles <akira.2020@xxxxxxxxxxxxxx>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218640
Signed-off-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>
Tested-by: anthony s. knowles <akira.2020@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240325183755.776-1-bp@xxxxxxxxx
---
 drivers/ras/debugfs.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/ras/debugfs.h b/drivers/ras/debugfs.h
index 4749ccdeeba1..5a2f48439258 100644
--- a/drivers/ras/debugfs.h
+++ b/drivers/ras/debugfs.h
@@ -4,6 +4,10 @@
 
 #include <linux/debugfs.h>
 
+#if IS_ENABLED(CONFIG_DEBUG_FS)
 struct dentry *ras_get_debugfs_root(void);
+#else
+static inline struct dentry *ras_get_debugfs_root(void) { return NULL; }
+#endif /* DEBUG_FS */
 
 #endif /* __RAS_DEBUGFS_H__ */
-- 
2.34.1