MIPS: Return -ENODEV from weak implementation of rtc_mips_set_time

The sync_cmos_clock function in kernel/time/ntp.c first tries to update
the internal clock of the cpu by calling the "update_persistent_clock64"
architecture specific function. If this returns -ENODEV, it then tries
to update an external RTC using "rtc_set_ntp_time".

On the mips architecture, the weak implementation of the underlying
function would return 0 if it wasn't overridden. This meant that the
sync_cmos_clock function would never try to update an external RTC
(if both CONFIG_GENERIC_CMOS_UPDATE and CONFIG_RTC_SYSTOHC are
configured)

Returning -ENODEV instead, means that an external RTC will be tried.

Signed-off-by: Luuk Paulussen <[e-mail]>
Reviewed-by: Richard Laing <[e-mail]>
Reviewed-by: Scott Parlane <[e-mail]>
Reviewed-by: Chris Packham <[e-mail]>
Cc: [e-mail]
Patchwork: https://patchwork.linux-mips.org/patch/14649/
Signed-off-by: Ralf Baechle <[e-mail]>

arch/mips/kernel/time.c

···
 
 int __weak rtc_mips_set_time(unsigned long sec)
 {
-	return 0;
+	return -ENODEV;
 }
 
 int __weak rtc_mips_set_mmss(unsigned long nowtime)