From: Bjorn Helgaas <bjorn.helgaas@hp.com>

The problem is that we don't clear out the efi_time_t buffer before asking
EFI to fill it in.  EFI doesn't always write the entire buffer (in
particular, the alarm time only supports one second resolution, so the
nanosecond field is often untouched).

The effect is that 'cat /proc/driver/efirtc' shows garbage in the
nanoseconds part of the alarm time, and sometimes artifacts like bogus
alarm date and junk after the actual end of the text.