ANDROID: GKI: Kconfig.gki: add hidden PHY configs

When testing GKI with out-of-tree PCIe support as modules, it was
discovered some hidden Kconfigs are required for DPHYs.  Add here so
out of tree PCIe drivers and PHYs can be built in a separate tree.

Bug: 179406580
Change-Id: Ic27c678b4e0dd4c29d354ff1139d453b99a3744f
Signed-off-by: Kevin Hilman <khilman@baylibre.com>