rtc: snvs: fix build with CONFIG_PM_SLEEP disabled

Commit 7654e9d4 ("drivers/rtc/rtc-snvs: fix suspend/resume")
replaces SIMPLE_DEV_PM_OPS with direct declaration of snvs_rtc_pm_ops,
but does so outside #ifdef CONFIG_PM_SLEEP.  This causes the driver
build to fail if CONFIG_PM_SLEEP is not configured.

Fixes: 7654e9d4

 ("drivers/rtc/rtc-snvs: fix suspend/resume")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Cc: Sanchayan Maity <maitysanchayan@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>