GetWakeupTime should return full time information, including
the daylight/timezone. Make use of the existing non-volatile
variables for that purpose. Moreover add an error checking
of possibly invalid parameters.
This partially fixes FWTS and SCT Set/GetWakeupTime tests on
Marvell platforms.
Signed-off-by: Marcin Wojtas <mw@semihalf.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org>