i3100: Add HAVE_HARD_RESET

i3100: Add HAVE_HARD_RESET

and remove it from mainboard/intel/mtarvon, as this function
is implemented in the southbridge code.

Change-Id: Id3669aaf99b96b4a7a965f4957e5de7c365acaa6
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Reviewed-on: http://review.coreboot.org/469
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>