mvumi: 64bit value for seconds_since1970

struct mvumi_hs_page2 stores a "seconds_since1970" field which is of
type u64. It is however, written to, using 'struct timeval' which has
a 32-bit seconds field and whose value will overflow in year 2038.
This patch uses ktime_get_real_seconds() instead since it provides a
64-bit seconds value, which is 2038 safe.

Signed-off-by: Tina Ruchandani <ruchandani.tina@gmail.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>