usb: gadget: ci13xxx: redo register access

Use lookup table instead of conditional macrodefinitions of register
addresses. With two different possible register layouts and different
register offsets, it's easiest to build a table with register addresses
at probe time, based on the information supplied from the platform and
device capabilities. This way we get rid of branch-per-register-access.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>