ANDROID: db845c: Fixup missing XHCI_HCD config and abi symbols

The XHCI_HCD config was pulled back out of gki_defconfig,
and without it USB host mode ports don't work on db845c.

This patch re-adds the module to the db845c_gki.fragment
and updates the KABI symbol list.

Signed-off-by: John Stultz <john.stultz@linaro.org>
Fixes: 552cb029 ("Revert "ANDROID: GKI: Enable CONFIG_USB_XHCI_HCD"")
Change-Id: Ibd2d543dbab0c6be918e8ba4bd45194d5994a0a3