AGESA f15tn f16kb: Fix HUDSON_XHCI_ENABLE

Control for XHCI was split to handle AMD_INIT_RESET in agesawrapper
while AMD_INIT_ENV was already handled as part of BiosCallouts.

OEM configuration is supposed to be implemented as part of BiosCallouts,
leaving agesawrapper agnostic of platform details.

TODO: S3 resume for XHCI1.

Change-Id: Id5e9c25a227db4d821f1be4b176470547ca4ea84
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/6241
Tested-by: build bot (Jenkins)
Reviewed-by: Rudolf Marek <r.marek@assembler.cz>