PXA255: support Intel "Lubbock" platform

PXA255: support Intel "Lubbock" platform

Config for Intel's "Lubbock" PXA255 development board.  Even more
so than the PXA255 itself, this is obsolete.  AFAIK this was the
first generally available development platform for PXA255.  Intel
stopped providing these after other devel boards became available.

One interesting thing about this board from the OpenOCD perspective
is probably its flash configuration.  Each bank is 32 bits wide,
built from two 16-bit StrataFlash chips wired in parallel.  This
doubles throughput ... it reads/writes 32 bits in the time a single
chip takes to write just 16 bits.

This conf mostly works, given XScale bugfixes, but has some issues
(notably: no access to the on-board SDRAM) flagged by FIXMEs.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>