Provide macro definitions regardless of whether caches are lockable or
not, make definitions empty in latter case.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

- make cache-related assembly macros empty if core doesn't have
  corresponding cache type;
- don't initialize cache attributes in instruction/data TLB entries if
  there's no corresponding cache type.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Remove heading and trailing spaces, trim trailing lines, and wrap lines
that are longer than 80 characters.

Signed-off-by: Chris Zankel <chris@zankel.net>

Move all header files for xtensa to arch/xtensa/include and platform and
variant header files to the appropriate arch/xtensa/platforms/ and
arch/xtensa/variants/ directories.

Moving the files gets also rid of all uses of symlinks in the Makefile.

This has been completed already for the majority of the architectures
and xtensa is one out of six missing.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Chris Zankel <chris@zankel.net>