pm_trace displays the wrong time from the RTC

The way in which read_magic_time() displays the date read from the RTC is
apparently confusing to the users (cf.
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=250238).  Make it
print dates in the standard way.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>