ceph: Use no_printk() helper

When printk-indexing is enabled, each printk() invocation emits a
pi_entry structure. This is even true when the call is protected by an
always-false check: while the actual code to print the message is
optimized out by the compiler, the pi_entry structure is still emitted.

Fix this by replacing "if (0) printk(...)" constructs by calls to the
no_printk() helper.

This reduces the size of an arm64 kernel with CONFIG_PRINTK_INDEX=y and
CONFIG_CEPH_FS=y by ca. 4 KiB.

Signed-off-by: Geert Uytterhoeven <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Reviewed-by: Xiubo Li <[e-mail]>
Reviewed-by: Chris Down <[e-mail]>
Reviewed-by: Petr Mladek <[e-mail]>
Link: https://lore.kernel.org/r/a2176[e-mail]
Signed-off-by: Petr Mladek <[e-mail]>

include/linux/ceph/ceph_debug.h

···
 		 ##__VA_ARGS__)
 # else
 /* faux printk call just to see any compiler warnings. */
-#  define dout(fmt, ...)	do {				\
-		if (0)						\
-			printk(KERN_DEBUG fmt, ##__VA_ARGS__);	\
-	} while (0)
-#  define doutc(client, fmt, ...)	do {			\
-		if (0)						\
-			printk(KERN_DEBUG "[%pU %llu] " fmt,	\
-			&client->fsid,				\
-			client->monc.auth->global_id,		\
-			##__VA_ARGS__);				\
-		} while (0)
+#  define dout(fmt, ...)					\
+		no_printk(KERN_DEBUG fmt, ##__VA_ARGS__)
+#  define doutc(client, fmt, ...)				\
+		no_printk(KERN_DEBUG "[%pU %llu] " fmt,		\
+			  &client->fsid,			\
+			  client->monc.auth->global_id,		\
+			  ##__VA_ARGS__)
 # endif
 
 #else