COBALT: remove all references to Cobalt NVRAM

Remove not only the references to Cobalt NVRAM, but the header file as
well.

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Acked-by: Tim Hockin <thockin@hockin.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>