[S390] sclp: fix compile error for !SCLP_CONSOLE

Define an empty static inline version of sclp_console_pm_event()
to fix the build error below for !SCLP_CONSOLE.

drivers/s390/built-in.o: In function `sclp_rw_pm_event':
sclp_rw.c:(.text+0x12f68): undefined reference to `sclp_console_pm_event'

Signed-off-by: Heiko Carstens <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

drivers/s390/char/sclp_rw.h

···
 void sclp_set_htab(struct sclp_buffer *, unsigned short);
 int sclp_chars_in_buffer(struct sclp_buffer *);
 
+#ifdef CONFIG_SCLP_CONSOLE
 void sclp_console_pm_event(enum sclp_pm_event sclp_pm_event);
+#else
+static inline void sclp_console_pm_event(enum sclp_pm_event sclp_pm_event) { }
+#endif
+
 #endif	/* __SCLP_RW_H__ */