xtensa: fix compilation somewhat

* ->put_char changes
 * HIGHMEM is bogus it seems, there is no kmap_atomic() et al
 * some includes

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Chris Zankel <zankel@tensilica.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>