cuda: fix off-by-one error in SET_TIME command

With the new framework the cuda_cmd_set_time command directly receive
the data, without the command byte. Therefore the time is stored at
in_data[0], not at in_data[1].

This fixes the "hwclock --systohc" command in a guest.

Cc: Hervé Poussineau <hpoussin@reactos.org>
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Hervé Poussineau <hpoussin@reactos.org>
[this fixes a regression introduced by e6473178 "cuda: port SET_TIME
 command to new framework"]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>