cris: move usec/nsec conversion to do_slow_gettimeoffset
Move usec to nsec conversion from arch_gettimeoffset() to
do_slow_gettimeoffset(); in a future patch, do_slow_gettimeoffset()
will be used directly as the implementation of arch_gettimeoffset(),
so needs to perform all required calculations.
Cc: Mikael Starvik <starvik@axis.com> Cc: linux-cris-kernel@axis.com Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Signed-off-by: Stephen Warren <swarren@nvidia.com>